Resin film, barrier film, electrically conductive film, and manufacturing method therefor

ABSTRACT

Provided is a barrier film including a resin film and a barrier layer provided on the resin film. Also provided is an electroconductive film including a resin film and an electroconductive layer provided on the resin film. The resin film is formed of a resin containing an alicyclic structure-containing polymer having crystallizability. An absolute value of a thermal size change ratio when the resin film is heated at 150° C. for 1 hour is 1% or less in any in-plane direction of the resin film.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Pat. No. 10,287,408 issuedMay 14, 2019, from U.S. application Ser. No. 15/521,432 filed Apr. 24,2017, which is a National Stage Application of PCT/JP2015/078713 filedOct. 9, 2015, which claims priority based on Japanese Patent ApplicationNo. 2014-219381 filed Oct. 28, 2014. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentirety.

FIELD

The present invention relates to a resin film; a barrier film and anelectroconductive film which are each provided with the resin film; andmethods for producing the resin film, the barrier film, and theelectroconductive film.

BACKGROUND

A technology of crystallizing an alicyclic structure-containing polymerin a film formed from a resin containing an alicyclicstructure-containing polymer having crystallizability by heating thefilm has been known (Patent Literatures 1 and 2). The film formed of theresin containing such an alicyclic structure-containing polymer havingcrystallizability usually has excellent heat resistance.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No.2002-194067 A

Patent Literature 2: Japanese Patent Application Laid-Open No.2013-010309 A

SUMMARY Technical Problem

In general, a film formed from a resin containing an alicyclicstructure-containing polymer having no crystallizability tends to havehigh coefficient of friction between the films. Therefore, when such afilm is wound into a roll shape, for example, the film is subjected toanti-blocking coating or bonded to a masking film, to prevent blockingof the films. The blocking of the films herein refers to a phenomenonwhere the film in contact with a certain surface adheres to thecontacted surface to be in a state of not being easily separable.

On the other hand, the inventors of the present invention have studiedand found that the coefficient of friction between films formed from aresin containing an alicyclic structure-containing polymer havingcrystallizability can be usually decreased. Therefore, the inventorshave tried to develop a film which can suppress occurrence of blockingusing the resin containing an alicyclic structure-containing polymerhaving crystallizability without a treatment of anti-blocking coating, amasking film, or the like.

In addition to blocking, a gauge band and a scratch may occur in a film.The gauge band of the film herein refers to a band-shaped concavo orconvex portion which extends in a circumferential direction that isformed on a surface of a film roll in which the film is wound into aroll shape. The scratch of the film refers to a scratched damage causedby rubbing of wound and stacked parts of the film which is wound into aroll shape. In order to suppress occurrence of the gauge band and thescratch, the inventors have tried a knurling treatment of the film.

The knurling treatment refers to a treatment of forming a protrusion ona film. The protrusion formed by the knurling treatment is formed so asto be protruded from a film surface around the protrusion. Thereby theapparent thickness of the film at a region where the protrusion isformed becomes large. For example, when a region near an end part of thefilm in the width direction thereof is subjected to the knurlingtreatment, it is expected that occurrence of a gauge band and a scratchis suppressed. Such a knurling treatment may be performed using, forexample, a laser beam. Specifically, the film is irradiated with a laserbeam to form a protrusion at a position which is irradiated with thelaser beam.

However, it was found that, when the film formed of the resin containingan alicyclic structure-containing polymer having crystallizability issubjected to the knurling treatment using a laser beam, deformation suchas waviness is likely to occur in the film. According to the studies bythe inventors, it is deduced that such deformation of the film occursbecause the resin containing an alicyclic structure-containing polymerhaving crystallizability is likely to be largely changed in size(usually, thermally shrunk) in a high-temperature environment. That is,it is deduced that, when the temperature of the film which has absorbedthe laser beam is increased, the film at a position where thetemperature is increased is largely changed in size, and the film isthus deformed due to the size change. Specifically, a prior-art filmcontaining an alicyclic structure-containing polymer is largely changedin size at a ratio of about 1.5% to 4% at a temperature within atemperature range that exceeds the glass transition temperature (forexample, 140° C. to 150° C.) thereof, and deformation sometimes occurs.When the film thus deformed is wound into a roll shape, winding may bemade uneven, or a crack may be generated in the film.

The present invention has been made in view of the aforementionedproblems. An object of the present invention is to provide a resin filmhaving excellent size stability in a high-temperature environment; abarrier film and an electroconductive film which are each provided withthe resin film; and methods for producing the resin film, the barrierfilm, and the electroconductive film.

Solution to Problem

(1) A resin film formed of a resin containing an alicyclicstructure-containing polymer having crystallizability, wherein

an absolute value of a thermal size change ratio when the film is heatedat 150° C. for 1 hour is 1% or less in any in-plane direction of thefilm.

-   (2) The resin film according to (1), wherein the alicyclic    structure-containing polymer is a hydrogenated product of a    ring-opened polymer of dicyclopentadiene.-   (3) The resin film according to (1) or (2), wherein the resin film    is an optical film.-   (4) A barrier film comprising:

the resin film according to any one of (1) to (3); and

a barrier layer provided on the resin film.

-   (5) An electroconductive film comprising:

the resin film according to any one of (1) to (3); and

an electroconductive layer provided on the resin film.

-   (6) A method for producing the resin film according to any one    of (1) to (3), comprising:

a step of setting a temperature of a first film formed of a resincontaining an alicyclic structure-containing polymer havingcrystallizability to a temperature which is equal to or higher than aglass transition temperature of the alicyclic structure-containingpolymer and equal to or lower than a melting point of the alicyclicstructure-containing polymer in a strained state where at least twosides of the first film are held, to obtain a crystallized film; and

a step of relaxing strain of the crystallized film while thecrystallized film is kept flat at a temperature which is equal to orhigher than the glass transition temperature of the alicyclicstructure-containing polymer and equal to or lower than the meltingpoint of the alicyclic structure-containing polymer.

-   (7) The method according to (6), comprising a step of stretching the    first film before the step of obtaining the crystallized film.-   (8) A method for producing a barrier film, comprising a step of    forming a barrier layer on the resin film according to any one    of (1) to (3).-   (9) A method for producing an electroconductive film, comprising a    step of forming an electroconductive layer on the resin film    according to any one of (1) to (3).

Advantageous Effects of Invention

The present invention can provide a resin film having excellent sizestability in a high-temperature environment; a barrier film and anelectroconductive film which are each provided with the resin film; andmethods for producing the resin film, the barrier film, and theelectroconductive film.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view schematically illustrating an example of a holdingdevice.

FIG. 2 is a plan view schematically illustrating an example of theholding device.

FIG. 3 is a front view schematically illustrating an example of a deviceof producing a resin film.

FIG. 4 is a plan view schematically illustrating the example of thedevice of producing a resin film.

FIG. 5 is a plan view schematically illustrating a part of a linkdevice.

FIG. 6 is a plan view schematically illustrating the part of the linkdevice.

FIG. 7 is a front view schematically illustrating an example of a schemeof producing a knurled film where a resin film is subjected to aknurling treatment.

FIG. 8 is a plan view schematically illustrating an example of a knurledfilm.

FIG. 9 is a cross-sectional view schematically illustrating an exampleof a film formation device capable of forming a barrier layer as aninorganic layer by a CVD method.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail withreference to embodiments and examples. However, the present invention isnot limited to the following embodiments and the examples describedbelow, and may be freely modified and practiced without departing fromthe scope of claims of the present invention and the scope of theirequivalents.

In the following description, a “long-length” film refers to a filmhaving a length of five times or more times the width of the film, andpreferably ten times or more times the width, and specifically a filmhaving a length long enough to be wound in a roll shape for storage ortransportation.

In the following description, the directions of an element being“parallel”, “perpendicular”, and “orthogonal” may allow errors withinthe bound of not impairing the effects of the present invention, forexample, within a range of ±5°, unless otherwise specified.

In the following description, a longitudinal direction of a long-lengthfilm is usually parallel to a conveyance direction of the film in aproduction line.

[1. Resin Film]

The resin film of the present invention is a film formed of a resincontaining an alicyclic structure-containing polymer havingcrystallizability. In the following description, the aforementionedresin may be referred to as “crystallizable resin”. The resin film ofthe present invention has excellent size stability in a high-temperatureenvironment. Specifically, when the resin film of the present inventionis heated at 150° C. for 1 hour, the absolute value of thermal sizechange ratio of the resin film is equal to or less than a specific valuein any in-plane direction of the film.

[1.1. Crystallizable Resin]

The crystallizable resin contains an alicyclic structure-containingpolymer having crystallizability. The alicyclic structure-containingpolymer herein refers to a polymer having an alicyclic structure in itsmolecule, and specifically a polymer which is obtainable by apolymerization reaction of a cyclic olefin used as a monomer, or ahydrogenated product thereof. As the alicyclic structure-containingpolymer, one type thereof may be solely used, and two or more typesthereof may also be used in combination at any ratio.

Examples of the alicyclic structure of the alicyclicstructure-containing polymer may include a cycloalkane structure and acycloalkene structure. Of these, a cycloalkane structure is preferablesince a resin film having excellent characteristics such as thermalstability is easily obtained. The number of carbon atoms contained inone alicyclic structure is preferably 4 or more, and more preferably 5or more, and is preferably 30 or less, more preferably 20 or less, andparticularly preferably 15 or less. When the number of carbon atomscontained in one alicyclic structure is within the aforementioned range,mechanical strength, heat resistance, and moldability are exhibited in ahighly balanced manner.

The ratio of a structural unit having the alicyclic structure relativeto all structural units in the alicyclic structure-containing polymer ispreferably 30% by weight or more, more preferably 50% by weight or more,and particularly preferably 70% by weight or more. When the ratio of thestructural unit having the alicyclic structure in the alicyclicstructure-containing polymer is made larger as described above, heatresistance can be enhanced.

The remaining part in the alicyclic structure-containing polymer, exceptfor the structural unit having the alicyclic structure, is notespecially limited, and may be appropriately selected depending on thepurposes of use.

The alicyclic structure-containing polymer contained in thecrystallizable resin has a crystallizability. The term “alicyclicstructure-containing polymer having crystallizability” as used hereinrefers to an alicyclic structure-containing polymer that has a meltingpoint Tm (i.e., the melting point can be observed with a differentialscanning calorimeter (DSC)). The melting point Tm of the alicyclicstructure-containing polymer is preferably 200° C. or higher, and morepreferably 230° C. or higher, and is preferably 290° C. or lower. Whenthe alicyclic structure-containing polymer having such a melting pointTm is used, a resin film having a particularly excellent balance betweenthe moldability and the heat resistance can be obtained.

The weight-average molecular weight (Mw) of the alicyclicstructure-containing polymer is preferably 1,000 or more, and morepreferably 2,000 or more, and is preferably 1,000,000 or less, and morepreferably 500,000 or less. The alicyclic structure-containing polymerhaving such a weight average molecular weight has an excellent balancebetween the molding workability and the heat resistance.

The molecular weight distribution (Mw/Mn) of the alicyclicstructure-containing polymer is preferably 1.0 or more, and morepreferably 1.5 or more, and is preferably 4.0 or less, and morepreferably 3.5 or less. Mn represents a number-average molecular weight.The alicyclic structure-containing polymer having such a molecularweight distribution has excellent molding workability.

The weight-average molecular weight (Mw) and the molecular weightdistribution (Mw/Mn) of the alicyclic structure-containing polymer maybe measured as a value in terms of polystyrene by gel permeationchromatography (GPC) using tetrahydrofuran as a developing solvent.

The glass transition temperature Tg of the alicyclicstructure-containing polymer is not particularly limited, and is usually85° C. or higher and is usually 170° C. or lower.

Examples of the alicyclic structure-containing polymer may include thefollowing polymers (α) to (δ). Of these, it is preferable that thecrystalline alicyclic structure-containing polymer is the polymer (β)since a resin film having excellent heat resistance is easily obtained.

Polymer (α): a ring-opened polymer of a cyclic olefin monomer, havingcrystallizability

Polymer (β): a hydrogenated product of the polymer (α), havingcrystallizability

Polymer (γ): an addition polymer of a cyclic olefin monomer, havingcrystallizability

Polymer (δ): a hydrogenated product or the like of the polymer (γ),having crystallizability

Specifically, the alicyclic structure-containing polymer is morepreferably a ring-opened polymer of dicyclopentadiene havingcrystallizability and a hydrogenated product of the ring-opened polymerof dicyclopentadiene having crystallizability, and particularlypreferably the hydrogenated product of the ring-opened polymer ofdicyclopentadiene having crystallizability. The ring-opened polymer ofdicyclopentadiene described herein refers to a polymer in which theratio of a structural unit derived from dicyclopentadiene relative toall structural units is usually 50% by weight or more, preferably 70% byweight or more, more preferably 90% by weight or more, and furtherpreferably 100% by weight.

The method for producing the polymer (α) and the polymer (β) will bedescribed below.

The cyclic olefin monomer usable in the production of the polymer (α)and the polymer (β) is a compound having a ring structure formed bycarbon atoms and has a carbon-carbon double bond in the ring. Examplesof the cyclic olefin monomer may include a norbornene-based monomer.When the polymer (α) is a copolymer, a cyclic olefin having a monocyclicstructure may be used as the cyclic olefin monomer.

The norbornene-based monomer is a monomer containing a norbornene ring.Examples of the norbornene-based monomer may include a bicyclic monomer,such as bicyclo[2.2.1]hept-2-ene (common name: norbornene), and5-ethylidene-bicyclo[2.2.1]hept-2-ene (common name: ethylidenenorbornene), and a derivative thereof (for example, the one having asubstituent in a ring); a tricyclic monomer, such astricyclo[4.3.0.1^(2,5)]deca-3,7-diene (common name: dicyclopentadiene)and a derivative thereof; and a tetracyclic monomer, such as7,8-benzotricyclo[4.3.0.1^(2,5)]dec-3-ene (common name:methanotetrahydrofluorene: also referred to as1,4-methano-1,4,4a,9a-tetrahydrofluorene) and a derivative thereof,tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-ene (common name:tetracyclododecene), and 8-ethylidenetetracyclo[4.4.0.1^(2,5).1^(7,10)]-3-dodecene and a derivative thereof.

Examples of the substituent in the monomer may include an alkyl group,such as a methyl group and an ethyl group; an alkenyl group, such as avinyl group; an alkylidene group, such as propan-2-ylidene; an arylgroup, such as a phenyl group; a hydroxy group; an acid anhydride group;a carboxyl group; and an alkoxycarbonyl group, such as a methoxycarbonylgroup. The monomer may have solely one type of the substituent, and mayalso have two or more types thereof in combination at any ratio.

Examples of the cyclic olefin having a monocyclic structure may includea cyclic monoolefin, such as cyclobutene, cyclopentene,methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, andcyclooctene; and a cyclic diolefin, such as cyclohexadiene,methylcyclohexadiene, cyclooctadiene, methylcyclooctadiene, andphenylcyclooctadiene.

As the cyclic olefin monomer, one type thereof may be solely used, andtwo or more types thereof may also be used in combination at any ratio.When two or more types of the cyclic olefin monomer are used, thepolymer (α) may be a block copolymer or a random copolymer.

The cyclic olefin monomer may have a structure with which endo and exostereoisomers may exist. As the cyclic olefin monomer, any of the endoand exo isomers may be used. Either one of the endo and exo isomers maybe solely used, and an isomer mixture containing the endo and exoisomers at any ratio may also be used. In particular, it is preferablethat the ratio of one stereoisomer is at a high level relative to theother since the crystallizability of the alicyclic structure-containingpolymer is enhanced and a resin film having particularly excellent heatresistance is easily obtained. For example, the ratio of the endo or exoisomer is preferably 80% or more, more preferably 90% or more, andfurther preferably 95% or more. It is preferable that the ratio of theendo isomer is high since synthesis is easy.

The crystallizability of the polymer (α) and the polymer (β) can beusually enhanced by increasing the degree of syndiotacticity (ratio ofracemo diads) of these polymers. From the viewpoint of increasing thedegree of stereoregularity of the polymer (α) and the polymer (β), theratio of racemo diads in the structural units of the polymer (α) and thepolymer (β) is preferably 51% or more, more preferably 60% or more, andparticularly preferably 70% or more.

The ratio of racemo diads may be measured by a ¹³C-NMR spectrumanalysis. Specifically, the measurement may be performed by thefollowing method.

A polymer sample is subjected to ¹³C-NMR measurement at 200° C. by aninverse-gated decoupling method using orthodichlorobenzene-d⁴ as asolvent. From the result of the ¹³C-NMR measurement, the ratio of racemodiads of the polymer sample may be obtained on the basis of an intensityratio of the signal at 43.35 ppm derived from meso diads and the signalat 43.43 ppm derived from racemo diads using the peak oforthodichlorobenzene-d⁴ at 127.5 ppm as a reference shift.

In synthesis of the polymer (α), a ring-opening polymerization catalystis usually used. As the ring-opening polymerization catalyst, one typethereof may be solely used, and two or more types thereof may also beused in combination at any ratio. It is preferable that such aring-opening polymerization catalyst for synthesis of the polymer (α) isa ring-opening polymerization catalyst which can achieve ring-openingpolymerization of the cyclic olefin monomer to produce a ring-openedpolymer having syndiotacticity. Preferable examples of the ring-openingpolymerization catalyst may include a ring-opening polymerizationcatalyst including a metal compound represented by the following formula(1):M(NR¹)X_(4-a)(OR²)_(a).Lb  (1)

(wherein

M is a metal atom selected from the group consisting of transition metalatoms of Group 6 of the periodic table,

R¹ is a phenyl group optionally having a substituent on at least one ofthe positions 3, 4, and 5, or a group represented by —CH₂R³ (R³ is agroup selected from the group consisting of a hydrogen atom, an alkylgroup optionally having a substituent, and an aryl group optionallyhaving a substituent),

R² is a group selected from the group consisting of an alkyl groupoptionally having a substituent and an aryl group optionally having asubstituent,

X is a group selected from the group consisting of a halogen atom, analkyl group optionally having a substituent, an aryl group optionallyhaving a substituent, and an alkylsilyl group,

L is a neutral electron donor ligand,

a is a number of 0 or 1, and

b is an integer of 0 to 2.)

In the formula (1), M is a metal atom selected from the group consistingof transition metal atoms of Group 6 of the periodic table. M ispreferably chromium, molybdenum, or tungsten, more preferably molybdenumor tungsten, and particularly preferably tungsten.

In the formula (1), R¹ is a phenyl group optionally having a substituenton at least one of the positions 3, 4, and 5, or a group represented by—CH₂R³.

The number of carbon atoms of the phenyl group optionally having asubstituent on at least one of the positions 3, 4, and 5 of R¹ ispreferably 6 to 20, and more preferably 6 to 15. Examples of thesubstituent may include an alkyl group, such as a methyl group and anethyl group; a halogen atom, such as a fluorine atom, a chlorine atom,and a bromine atom; and an alkoxy group, such as a methoxy group, anethoxy group, and an isopropoxy group. The group may have solely onetype of the substituent, and may also have two or more types thereof incombination at any ratio. In R¹, the substituents present on at leasttwo of the positions 3, 4, and 5 may be bonded to each other, to form aring structure.

Examples of the phenyl group optionally having a substituent on at leastone of the positions 3, 4, and 5 may include an unsubstituted phenylgroup; a monosubstituted phenyl group, such as a 4-methylphenyl group, a4-chlorophenyl group, a 3-methoxyphenyl group, a 4-cyclohexylphenylgroup, and a 4-methoxyphenyl group; a disubstituted phenyl group, suchas a 3,5-dimethylphenyl group, a 3,5-dichlorophenyl group, a3,4-dimethylphenyl group, and a 3,5-dimethoxyphenyl group; atrisubstituted phenyl group, such as a 3,4,5-trimethylphenyl group, anda 3,4,5-trichlorophenyl group; and a 2-naphthyl group optionally havinga substituent, such as a 2-naphthyl group, a 3-methyl-2-naphthyl group,and a 4-methyl-2-naphthyl group.

In the group represented by —CH₂R³ of R¹, R³ is a group selected fromthe group consisting of a hydrogen atom, an alkyl group optionallyhaving a substituent, and an aryl group optionally having a substituent.

The number of carbon atoms in the alkyl group optionally having asubstituent of R³ is preferably 1 to 20, and more preferably 1 to 10.The alkyl group may be either linear or branched. Examples of thesubstituent may include a phenyl group optionally having a substituent,such as a phenyl group and a 4-methylphenyl group; and an alkoxyl group,such as a methoxy group and an ethoxy group. As the substituent, onetype thereof may be solely used, and two or more types thereof may alsobe used in combination at any ratio.

Examples of the alkyl group optionally having a substituent of R³ mayinclude a methyl group, an ethyl group, a propyl group, an isopropylgroup, a butyl group, an isobutyl group, a tert-butyl group, a pentylgroup, a neopentyl group, a benzyl group, and a neophyl group.

The number of carbon atoms in the aryl group optionally having asubstituent of R³ is preferably 6 to 20, and more preferably 6 to 15.Examples of the substituent may include an alkyl group, such as a methylgroup and an ethyl group; a halogen atom, such as a fluorine atom, achlorine atom, and a bromine atom; and an alkoxy group, such as amethoxy group, an ethoxy group, and an isopropoxy group. As thesubstituent, one type thereof may be solely used, and two or more typesthereof may also be used in combination at any ratio.

Examples of the aryl group optionally having a substituent of R³ mayinclude a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a4-methylphenyl group, and a 2,6-dimethylphenyl group.

Of these, the group represented by R³ is preferably an alkyl grouphaving 1 to 20 carbon atoms.

In the formula (1), R² is a group selected from the group consisting ofan alkyl group optionally having a substituent and an aryl groupoptionally having a substituent. As each of the alkyl group optionallyhaving a substituent and the aryl group optionally having a substituentof R², a group selected from groups exemplified as the alkyl groupoptionally having a substituent and the aryl group optionally having asubstituent of R³ may be optionally used.

In the formula (1), X is a group selected from the group consisting of ahalogen atom, an alkyl group optionally having a substituent, an arylgroup optionally having a substituent, and an alkylsilyl group.

Examples of the halogen atom of X may include a chlorine atom, a bromineatom, and an iodine atom.

As each of the alkyl group optionally having a substituent and the arylgroup optionally having a substituent of X, a group selected from groupsexemplified as the alkyl group optionally having a substituent and thearyl group optionally having a substituent of R³ may be optionally used.

Examples of the alkylsilyl group of X may include a trimethylsilylgroup, a triethylsilyl group, and a tert-butyldimethylsilyl group.

When the metal compound represented by the formula (1) has two or moreX's in one molecule, these X's may be the same or different from eachother. Further, the two or more X's may be bonded to each other to forma ring structure.

In the formula (1), L is a neutral electron donor ligand.

Examples of the neutral electron donor ligand of L may include anelectron donor compound containing an atom of Group 14 or 15 of theperiodic table. Specific examples thereof may include phosphines, suchas trimethylphosphine, triisopropylphosphine, tricyclohexylphosphine,and triphenylphosphine; ethers, such as diethyl ether, dibutyl ether,1,2-dimethoxyethane, and tetrahydrofuran; and amines, such astrimethylamine, triethylamine, pyridine, and lutidine. Of these, ethersare preferable. When the metal compound represented by the formula (1)has two or more L's in one molecule, these L's may be the same ordifferent from each other.

The metal compound represented by the formula (1) is preferably atungsten compound having a phenylimide group. That is, it is preferablethat the compound of the formula (1) is a compound wherein M is atungsten atom and R¹ is a phenyl group. In particular, a tetrachlorotungsten phenylimide(tetrahydrofuran) complex is more preferable.

The method for producing the metal compound represented by the formula(1) is not particularly limited. As described in Japanese PatentApplication Laid-open No. Hei. 5-345817 A, for example, the metalcompound represented by the formula (1) may be produced by mixing anoxyhalogenated product of a Group 6 transition metal; a phenylisocyanate optionally having a substituent on at least one of thepositions 3, 4, and 5 or a monosubstituted methyl isocyanate; a neutralelectron donor ligand (L); and if necessary, an alcohol, a metalalkoxide, and a metal aryloxide.

In the aforementioned production method, the metal compound representedby the formula (1) is usually obtained in a state where the compound iscontained in a reaction liquid. After production of the metal compound,the aforementioned reaction liquid as it is may be used as a catalystliquid for a ring-opening polymerization reaction. Alternatively, themetal compound may be isolated and purified from the reaction liquid bya purification treatment, such as crystallization, and the obtainedmetal compound may then be supplied to the ring-opening polymerizationreaction.

As the ring-opening polymerization catalyst, the metal compoundrepresented by the formula (1) may be solely used, and the metalcompound represented by the formula (1) may also be used in combinationwith other components. For example, the metal compound may be used incombination with an organometallic reducing agent, to improve thepolymerization activity.

Examples of the organometallic reducing agent may include organometalliccompounds of Groups 1, 2, 12, 13, and 14 in the periodic table, having ahydrocarbon group of 1 to 20 carbon atoms. Examples of suchorganometallic compounds may include an organolithium, such asmethyllithium, n-butyllithium, and phenyllithium; an organomagnesium,such as butylethylmagnesium, butyloctylmagnesium, dihexylmagnesium,ethylmagnesium chloride, n-butylmagnesium chloride, and allylmagnesiumbromide; an organozinc, such as dimethylzinc, diethylzinc, anddiphenylzinc; an organoaluminum, such as trimethylammonium,triethylammonium, triisobutylammonium, diethylammonium chloride,ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminumethoxide, diisobutylaluminum isobutoxide, ethylaluminum diethoxide, andisobutylaluminum diisobutoxide; and an organotin, such astetramethyltin, tetra(n-butyl)tin, and tetraphenyltin. Of these, anorganoaluminum and an organotin are preferable. As the organometallicreducing agent, one type thereof may be solely used, and two or moretypes thereof may also be used in combination at any ratio.

The ring-opening polymerization reaction is usually performed in anorganic solvent. As the organic solvent, an organic solvent which candissolve or disperse the ring-opened polymer and a hydrogenated productthereof under specific conditions and does not inhibit the ring-openingpolymerization reaction and a hydrogenation reaction may be used.Examples of such an organic solvent may include aliphatic hydrocarbons,such as pentane, hexane, and heptane; alicyclic hydrocarbons, such ascyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane,trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane,decahydronaphthalene, bicycloheptane, tricyclodecane, hexahydroindene,and cyclooctane; aromatic hydrocarbons, such as benzene, toluene, andxylene; halogen-containing aliphatic hydrocarbons, such asdichloromethane, chloroform, and 1,2-dichloroethane; halogen-containingaromatic hydrocarbons, such as chlorobenzene and dichlorobenzene;nitrogen-containing hydrocarbons, such as nitromethane, nitrobenzene,and acetonitrile; ethers, such as diethyl ether and tetrahydrofuran; andmixed solvents that are combinations of the foregoing. Of these, as theorganic solvent, aromatic hydrocarbons, aliphatic hydrocarbons,alicyclic hydrocarbons, and ethers are preferable. As the organicsolvent, one type thereof may be solely used, and two or more typesthereof may also be used in combination at any ratio.

The ring-opening polymerization reaction may be initiated by, forexample, mixing the cyclic olefin monomer, the metal compoundrepresented by the formula (1), and if necessary, the organometallicreducing agent. The order of mixing these components is not particularlylimited. For example, a solution containing the metal compoundrepresented by the formula (1) and the organometallic reducing agent maybe mixed in a solution containing the cyclic olefin monomer.Alternatively, a solution containing the cyclic olefin monomer and themetal compound represented by the formula (1) may be mixed in a solutioncontaining the organometallic reducing agent. Further, a solutioncontaining the metal compound represented by the formula (1) may bemixed with a solution containing the cyclic olefin monomer and theorganometallic reducing agent. When mixing these components, the totalamount of each component may be mixed at a time or over a plurality oftimes. The components may also be continuously mixed over a relativelylong period of time (for example, 1 minute or more).

The concentration of the cyclic olefin monomer in the reaction liquid atthe starting point of the ring-opening polymerization reaction ispreferably 1% by weight or more, more preferably 2% by weight or more,and particularly preferably 3% by weight or more, and is preferably 50%by weight or less, more preferably 45% by weight or less, andparticularly preferably 40% by weight or less. When the concentration ofthe cyclic olefin monomer is equal to or more than the lower limit valueof the aforementioned range, productivity can be improved. When it isequal to or less than the upper limit value thereof, the viscosity ofthe reaction liquid after the ring-opening polymerization reaction canbe lowered. Consequently, a subsequent hydrogenation reaction can beeasily performed.

It is desirable that the amount of the metal compound represented by theformula (1) used in the ring-opening polymerization reaction is set suchthat the molar ratio of “metal compound: cyclic olefin monomer” fallswithin a specific range. Specifically, the molar ratio is preferably1:100 to 1:2,000,000, more preferably 1:500 to 1,000,000, andparticularly preferably 1:1,000 to 1:500,000. When the amount of themetal compound is equal to or more than the lower limit value of theaforementioned range, sufficient polymerization activity can beobtained. When it is equal to or less than the upper limit valuethereof, the metal compound can be easily removed after the reaction.

The amount of the organometallic reducing agent is preferably 0.1 mol ormore, more preferably 0.2 mol or more, and particularly preferably 0.5mol or more, and is preferably 100 mol or less, more preferably 50 molor less, and particularly preferably 20 mol or less, relative to 1 molof the metal compound represented by the formula (1). When the amount ofthe organometallic reducing agent is equal to or more than the lowerlimit value of the aforementioned range, polymerization activity can besufficiently increased. When it is equal to or less than the upper limitvalue thereof, occurrence of a side reaction can be suppressed.

The polymerization reaction system of the polymer (α) may contain anactivity modifier. When the activity modifier is used, the ring-openingpolymerization catalyst can be stabilized, the reaction rate of thering-opening polymerization reaction can be adjusted, and the molecularweight distribution of the polymer can be adjusted.

As the activity modifier, an organic compound having a functional groupmay be used. Examples of the activity modifier may include anoxygen-containing compound, a nitrogen-containing compound, and aphosphorus-containing organic compound.

Examples of the oxygen-containing compound may include ethers, such asdiethyl ether, diisopropyl ether, dibutyl ether, anisole, furan, andtetrahydrofuran; ketones, such as acetone, benzophenone, andcyclohexanone; and esters, such as ethyl acetate.

Examples of the nitrogen-containing compound may include nitriles, suchas acetonitrile and benzonitrile; amines, such as triethylamine,triisopropylamine, quinuclidine, and N,N-diethylaniline; and pyridines,such as pyridine, 2,4-lutidine, 2,6-lutidine, and 2-tert-butylpyridine.

Examples of the phosphorus-containing compound may include phosphines,such as triphenylphosphine, tricyclohexylphosphine, triphenyl phosphate,and trimethyl phosphate; and phosphine oxides, such astriphenylphosphine oxide.

As the activity modifier, one type thereof may be solely used, and twoor more types thereof may also be used in combination at any ratio.

The amount of the activity modifier in the polymerization reactionsystem of the polymer (α) is preferably 0.01 mol % to 100 mol % relativeto 100 mol % of the metal compound represented by the formula (1).

The polymerization reaction system of the polymer (α) may contain amolecular weight modifier to adjust the molecular weight of the polymer(α). Examples of the molecular weight modifier may include α-olefins,such as 1-butene, 1-pentene, 1-hexene, and 1-octene; an aromatic vinylcompound, such as styrene and vinyltoluene; an oxygen-containing vinylcompound, such as ethyl vinyl ether, isobutyl vinyl ether, allylglycidyl ether, allyl acetate, allyl alcohol, and glycidyl methacrylate;a halogen-containing vinyl compound, such as allyl chloride; anitrogen-containing vinyl compound, such as acrylamide; a non-conjugateddiene, such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene,1,6-heptadiene, 2-methyl-1,4-pentadiene, and 2,5-dimethyl-1,5-hexadiene;and a conjugated diene, such as 1,3-butadiene, 2-methyl-1,3-butadiene,2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene.

As the molecular weight modifier, one type thereof may be solely used,and two or more types thereof may also be used in combination at anyratio.

The amount of the molecular weight modifier in the polymerizationreaction system for polymerizing the polymer (α) may be appropriatelydetermined in accordance with a target molecular weight. Specifically,the amount of the molecular weight modifier preferably falls within arange of 0.1 mol % to 50 mol % relative to the cyclic olefin monomer.

The polymerization temperature is preferably −78° C. or higher, and morepreferably −30° C. or higher, and is preferably +200° C. or lower, andmore preferably +180° C. or lower.

The polymerization time may depend on the reaction scale. Specifically,the polymerization time preferably falls within a range of 1 minute to1,000 hours.

The polymer (α) may be obtained by the aforementioned production method.When the polymer (α) is hydrogenated, the polymer (β) may be produced.

For example, the polymer (α) may be hydrogenated by supplying hydrogento the reaction system containing the polymer (α) in the presence of ahydrogenation catalyst in accordance with an ordinary method. Thehydrogenation reaction usually does not affect the tacticity of thehydrogenated product as long as reaction conditions of the hydrogenationreaction are set appropriately.

As the hydrogenation catalyst, a homogeneous catalyst or heterogeneouscatalyst which is known as a hydrogenation catalyst for an olefincompound may be used.

Examples of the homogeneous catalyst may include a catalyst including acombination of a transition metal compound and an alkali metal compound,such as cobalt acetate/triethylaluminum, nickelacetylacetonate/triisobutylaluminum, titanocenedichloride/n-butyllithium, zirconocene dichloride/sec-butyllithium, andtetrabutoxytitanate/dimethylmagnesium; and a noble metal complexcatalyst, such as dichlorobis(triphenylphosphine) palladium,chlorohydridecarbonyltris(triphenylphosphine) ruthenium,chlorohydridecarbonylbis(tricyclohexylphosphine) ruthenium,bis(tricyclohexylphosphine)benzylidine ruthenium (IV) dichloride, andchlorotris(triphenylphosphine) rhodium.

Examples of the heterogeneous catalyst may include a metal catalyst,such as nickel, palladium, platinum, rhodium, and ruthenium; and a solidcatalyst in which the aforementioned metal is supported on a carrier,such as carbon, silica, diatomaceous earth, alumina, and titanium oxide,examples of which may include nickel/silica, nickel/diatomaceous earth,nickel/alumina, palladium/carbon, palladium/silica,palladium/diatomaceous earth, and palladium/alumina.

As the hydrogenation catalyst, one type thereof may be solely used, andtwo or more types thereof may also be used in combination at any ratio.

The hydrogenation reaction is usually performed in an inert organicsolvent. Examples of the inert organic solvent may include aromatichydrocarbons, such as benzene and toluene; aliphatic hydrocarbons, suchas pentane and hexane; alicyclic hydrocarbons, such as cyclohexane anddecahydronaphthalene; and ethers, such as tetrahydrofuran and ethyleneglycol dimethyl ether. As the inert organic solvent, one type thereofmay be solely used, and two or more types thereof may also be used incombination at any ratio. The inert organic solvent may be the same as,and may also be different from the organic solvent used in thering-opening polymerization reaction. Further, the hydrogenationcatalyst may be mixed with the reaction liquid of the ring-openingpolymerization reaction to perform the hydrogenation reaction.

The reaction conditions for the hydrogenation reaction usually varydepending on the hydrogenation catalyst to be used.

The reaction temperature of the hydrogenation reaction is preferably−20° C. or higher, more preferably −10° C. or higher, and particularlypreferably 0° C. or higher, and is preferably +250° C. or lower, morepreferably +220° C. or lower, and particularly preferably +200° C. orlower. When the reaction temperature is equal to or more than the lowerlimit value of the aforementioned range, the reaction rate can beincreased. When it is equal to or less than the upper limit valuethereof, occurrence of a side reaction can be suppressed.

The hydrogen pressure is preferably 0.01 MPa or more, more preferably0.05 MPa or more, and particularly preferably 0.1 MPa or more, and ispreferably 20 MPa or less, more preferably 15 MPa or less, andparticularly preferably 10 MPa or less. When the hydrogen pressure isequal to or more than the lower limit value of the aforementioned range,the reaction rate can be increased. When it is equal to or less than theupper limit value thereof, a special device such as a high pressureresistant reaction device is not necessary. Therefore, facility costscan be reduced.

The reaction time of the hydrogenation reaction may be set to any timelength in which a desired hydrogenation ratio is achieved, and ispreferably 0.1 hours to 10 hours.

After the hydrogenation reaction, the polymer (β) which is thehydrogenated product of the polymer (α) is usually collected inaccordance with an ordinary method.

The hydrogenation ratio (the ratio of main-chain double bonds that arehydrogenated) in the hydrogenation reaction is preferably 98% or more,and more preferably 99% or more. When the polymer has a highhydrogenation ratio, heat resistance of the alicyclicstructure-containing polymer can be improved.

Herein, the hydrogenation ratio of the polymer may be measured by ¹H-NMRmeasurement at 145° C. using orthodichlorobenzene-d⁴ as a solvent.

Subsequently, the method for producing the polymer (γ) and the polymer(δ) will be described.

As a cyclic olefin monomer used in the production of the polymer (γ) andthe polymer (δ), any cyclic olefin monomer selected from thoseexemplified as the cyclic olefin monomers usable in the production ofthe polymer (α) and the polymer (β) may be used. As the cyclic olefinmonomer, one type thereof may be solely used, and two or more typesthereof may also be used in combination at any ratio.

In the production of the polymer (γ), an optional monomercopolymerizable with the cyclic olefin monomer may be used as a monomerin combination with the cyclic olefin monomer. Examples of the optionalmonomer may include an α-olefin having 2 to 20 carbon atoms, such asethylene, propylene, 1-butene, 1-pentene, and 1-hexene; an aromaticvinyl compound, such as styrene and a-methylstyrene; and anon-conjugated diene, such as 1,4-hexadiene, 4-methyl-1,4-hexadiene,5-methyl-1,4-hexadiene, and 1,7-octadiene. Of these, an α-olefin ispreferable, and ethylene is more preferable. As the optional monomer,one type thereof may be solely used, and two or more types thereof mayalso be used in combination at any ratio.

The weight ratio of the cyclic olefin monomer relative to the optionalmonomer (cyclic olefin monomer:optional monomer) is preferably 30:70 to99:1, more preferably 50:50 to 97:3, and particularly preferably 70:30to 95:5.

In cases wherein two or more types of the cyclic olefin monomer areused, and in cases wherein the cyclic olefin monomer and the optionalmonomer are used in combination, the polymer (γ) may be a blockcopolymer, and may also be a random copolymer.

In the synthesis of the polymer (γ), an addition polymerization catalystis usually used. Examples of the addition polymerization catalyst mayinclude a vanadium-based catalyst formed from a vanadium compound and anorganoaluminum compound, a titanium-based catalyst formed from atitanium compound and an organoaluminum compound, and a zirconium-basedcatalyst formed from a zirconium complex and an aluminoxane. As theaddition polymer catalyst, one type thereof may be solely used, and twoor more types thereof may also be used in combination at any ratio.

The amount of the addition polymerization catalyst is preferably0.000001 mol or more, and more preferably 0.00001 mol or more, and ispreferably 0.1 mol or less, and more preferably 0.01 mol or less,relative to 1 mol of the monomer.

The addition polymerization of the cyclic olefin monomer is usuallyperformed in an organic solvent. As the organic solvent, any organicsolvent selected from those exemplified as the organic solvents usablein the ring-opening polymerization of the cyclic olefin monomer may beused. As the organic solvent, one type thereof may be solely used, andtwo or more types thereof may also be used in combination at any ratio.

The polymerization temperature in the polymerization for producing thepolymer (γ) is preferably −50° C. or higher, more preferably −30° C. orhigher, and particularly preferably −20° C. or higher, and is preferably250° C. or lower, more preferably 200° C. or lower, and particularlypreferably 150° C. or lower. The polymerization time is preferably 30minutes or more, and more preferably 1 hour or more, and is preferably20 hours or less, and more preferably 10 hours or less.

The polymer (γ) may be obtained by the aforementioned production method.The polymer (δ) may be produced by hydrogenating the polymer (γ).

Hydrogenation of the polymer (γ) may be performed by the same method asdescribed for the hydrogenation of the polymer (α).

The ratio of the alicyclic structure-containing polymer havingcrystallizability in the crystallizable resin is preferably 50% byweight or more, more preferably 70% by weight or more, and particularlypreferably 90% by weight or more. When the ratio of the alicyclicstructure-containing polymer having crystallizability is equal to ormore than the lower limit value of the aforementioned range, the heatresistance of the resin film of the present invention can be enhanced.

The alicyclic structure-containing polymer contained in thecrystallizable resin does not have to be crystallized before theproduction of the resin film of the present invention. However, afterthe production of the resin film of the present invention, the alicyclicstructure-containing polymer contained in the crystallizable resinconstituting the resin film may usually have high crystallinity degreeas a result of crystallization. Specific range of crystallinity degreemay be appropriately selected in accordance with a desired performance,and is preferably 10% or more, and more preferably 15% or more. When thecrystallinity degree of the alicyclic structure-containing polymercontained in the resin film is equal to or more than the lower limitvalue of the aforementioned range, high heat resistance and chemicalresistance can be imparted to the resin film.

The crystallinity degree of the alicyclic structure-containing polymercontained in the resin film may be measured by an X-ray diffractionmethod.

In addition to the alicyclic structure-containing polymer havingcrystallizability, the crystallizable resin may contain an optionalcomponent. Examples of the optional component may include anantioxidant, such as a phenolic antioxidant, a phosphorus-basedantioxidant, and a sulfur-based antioxidant; a light stabilizer, such asa hindered amine-based light stabilizer; a wax, such as apetroleum-based wax, a Fischer-Tropsch wax, and a polyalkylene wax; anucleating agent, such as a sorbitol-based compound, a metal salt of anorganic phosphoric acid, a metal salt of an organic carboxylic acid,kaolin, and talc; a fluorescent brightening agent, such as adiaminostilbene derivative, a coumarin derivative, an azole-basedderivative (for example, a benzoxazole derivative, a benzotriazolederivative, a benzimidazole derivative, and a benzothiazole derivative),a carbazole derivative, a pyridine derivative, a naphthalic acidderivative, and an imidazolone derivative; a ultraviolet absorbingagent, such as a benzophenone-based ultraviolet absorbing agent, asalicylic acid-based ultraviolet absorbing agent, and abenzotriazole-based ultraviolet absorbing agent; an inorganic filler,such as talc, silica, calcium carbonate, and glass fibers; a colorant; aflame retardant; a flame retardant promoter; an antistatic agent; aplasticizer; a near-infrared absorbing agent; a lubricant; a filler; andan optional polymer other than the alicyclic structure-containingpolymer having crystallizability, such as a soft polymer. As theoptional component, one type thereof may be solely used, and two or moretypes thereof may also be used in combination at any ratio.

[1.2. Properties of Resin Film]

The resin film of the present invention is formed of the aforementionedcrystallizable resin. Prior-art films formed of a crystallizable resingenerally tend to have poor size stability in a high-temperatureenvironment that is equal to or higher than the glass transitiontemperature of the crystallizable resin. However, nevertheless the resinfilm of the present invention is a film formed of the crystallizableresin, it has excellent size stability in a high-temperature environmentthat is equal to or higher than the glass transition temperature of thecrystallizable resin. Specifically, when the resin film of the presentinvention is heated at 150° C. for 1 hour, the absolute value of thermalsize change ratio of the resin film is usually 1% or less, preferably0.5% or less, and more preferably 0.1% or less in any in-plane directionof the film. The resin film of the present invention is usually shrunkin a high-temperature environment. Therefore, the thermal size changeratio is usually a negative value.

The thermal size change ratio of the resin film may be measured by thefollowing method.

The resin film is cut out to be a square shape with a size of 150 mm×150mm in an environment at a room temperature of 23° C., to obtain a samplefilm. This sample film is heated in an oven of 150° C. for 60 minutes,and cooled to 23° C. (room temperature). The lengths of four sides andtwo diagonal lines of the sample film are measured.

The thermal size change ratio of the sample film is calculated by thefollowing equation (I) on the basis of the measured length of each offour sides. In the equation (I), L_(A) is the length of each side of theheated sample film.Thermal size change ratio (%)=[(L _(A)−150)/150]×100  (I)

The thermal size change ratio of the sample film is also calculated bythe following equation (II) on the basis of the measured length of eachof two diagonal lines. In the equation (II), L_(D) is the length of eachdiagonal line of the heated sample film.Thermal size change ratio (%)=[(L _(D)−212.13)/212.13]×100  (II)

The value whose absolute value is maximum among six calculated values ofthermal size change ratio is employed as the thermal size change ratioof the resin film.

It is preferable that the resin film of the present invention hasexcellent transparency. Specifically, the total light transmittance ofthe resin film of the present invention is preferably 80% or more, morepreferably 85% or more, and particularly preferably 88% or more.

The total light transmittance of the resin film may be measured at awavelength range of 400 nm to 700 nm with an ultraviolet-visiblespectrophotometer.

It is preferable that the resin film of the present invention has lowhaze. Specifically, the haze of the resin film of the present inventionis preferably 5% or less, more preferably 3% or less, and particularlypreferably 1% or less.

The haze of the resin film may be obtained by cutting out a randomlyselected portion of the resin film to obtain a thin-layer sample havinga square shape with a size of 50 mm×50 mm, and then performingmeasurement for the thin-layer sample with a haze meter.

The resin film of the present invention may have retardation dependingon the application. For example, when the resin film of the presentinvention is used as an optical film such as a phase difference film andan optical compensation film, it is preferable that the resin film hasretardation.

The thickness of the resin film of the present invention may beappropriately selected depending on the desire application, and ispreferably 1 μm or more, more preferably 3 μm or more, and particularlypreferably 10 μm or more, and is preferably 1 mm or less, morepreferably 500 μm or less, and particularly preferably 200 μm or less.When the thickness of the resin film is equal to or more than the lowerlimit value of the aforementioned range, appropriate strength can beobtained. When it is equal to or less than the upper limit valuethereof, a long-length film can be wound in the production thereof.

The resin film of the present invention may be used for any purpose. Inparticular, the resin film of the present invention is suitable, forexample, as an optical film, such as an optically isotropic film and aphase difference film, an electrical/electronics film, a substrate filmfor a barrier film, and a substrate film for an electroconductive film.Examples of the optical film may include a phase difference film for aliquid crystal display device, a polarizing plate protection film, and aphase difference film for a circularly polarizing plate of an organic ELdisplay device. Examples of the electrical/electronics film may includea flexible circuit board and an insulation material for a filmcapacitor. Examples of the barrier film may include a substrate for anorganic EL element, a sealing film, and a sealing film of a solar cell.Examples of the electroconductive film may include a flexible electrodeof an organic EL element or a solar cell and a touch panel member.

[2. Method for Producing Resin Film]

The resin film of the present invention may be produced, for example, bya production method including: a step (crystallization step) of settingthe temperature of a first film formed of the crystallizable resincontaining the alicyclic structure-containing polymer havingcrystallizability to a temperature which is equal to or higher than theglass transition temperature Tg of the alicyclic structure-containingpolymer and equal to or lower than the melting point Tm of the alicyclicstructure-containing polymer in a strained state where at least twosides of the first film are held, to obtain a crystallized film; and astep (relaxation step) of relaxing the strain of the crystallized filmwhile the crystallized film is kept flat at a temperature which is equalto or higher than the glass transition temperature Tg of the alicyclicstructure-containing polymer and equal to or lower than the meltingpoint Tm of the alicyclic structure-containing polymer. In theproduction of a resin film using a crystallizable resin which can beshrunk in a high-temperature environment, the resin film of the presentinvention can be easily produced according to this production method.

Hereinafter, this production method will be described.

[2.1. Preparation of Primary Film]

In the aforementioned production method, a step of preparing a primaryfilm as the first film is performed. The primary film is a film formedof the crystallizable resin. For example, the primary film may beproduced by a resin molding method, such as an injection molding method,an extrusion molding method, a press molding method, an inflationmolding method, a blow molding method, a calendar molding method, a castmolding method, and a compression molding method. Of these, it ispreferable that the primary film is produced by an extrusion moldingmethod since the thickness can be easily controlled.

When the primary film is produced by an extrusion molding method,preferable production conditions in the extrusion molding method are asfollows. The temperature of a cylinder (molten resin temperature) ispreferably Tm or higher, and more preferably “Tm+20”° C. or higher, andis preferably “Tm+100”° C. or lower, and more preferably “Tm+50”° C. orlower. The temperature of a cast roll is preferably “Tg−50”° C. orhigher, and is preferably “Tg+70”° C. or lower, and more preferably“Tg+40”° C. or lower. The temperature of a cooling roll is preferably“Tg−70”° C. or higher, and more preferably “Tg−50”° C. or higher, and ispreferably “Tg+60”° C. or lower, and more preferably “Tg+30”° C. orlower. When the primary film is produced under such conditions, aprimary film having a thickness of 1 μm to 1 mm can be easily produced.Herein, “Tm” represents the melting point of the alicyclicstructure-containing polymer, and “Tg” represents the glass transitiontemperature of the alicyclic structure-containing polymer.

The primary film produced as described above as it is may be supplied tothe crystallization step. Alternatively, the primary film may be, forexample, supplied to the crystallization step after an optionaltreatment such as a stretching treatment.

The method of stretching the primary film is not particularly limited,and any stretching method may be used. Examples of the stretching methodmay include a uniaxial stretching method such as a method of uniaxiallystretching the primary film in a longitudinal direction (longitudinaluniaxial stretching method) and a method of uniaxially stretching theprimary film in a width direction (transverse uniaxial stretchingmethod); a biaxial stretching method such as a simultaneous biaxialstretching method of stretching the primary film in the width directionat the same time as stretching the primary film in the longitudinaldirection and a sequential biaxial stretching method of stretching theprimary film in one of the longitudinal and width directions, followedby stretching the primary film in the other direction; and a method ofstretching the primary film in a diagonal direction that is neitherparallel nor perpendicular to the width direction (diagonal stretchingmethod).

Examples of the longitudinal uniaxial stretching method may include astretching method utilizing the difference in peripheral speed betweenrolls.

Examples of the transverse uniaxial stretching method may include astretching method using a tenter stretching machine.

Examples of the simultaneous biaxial stretching method may include astretching method in which the primary film is stretched in thelongitudinal direction using a tenter stretching machine provided with aplurality of clips which are provided so as to be movable along a guiderail and can fix the primary film, by increasing intervals between theclips, and simultaneously stretched in the width direction by utilizinga spreading angle of the guide rails.

Examples of the sequential biaxial stretching method may include astretching method in which the primary film is stretched in thelongitudinal direction by utilizing the difference in a peripheral speedbetween rolls, and then stretched in the width direction by a tenterstretching machine holding both ends of the primary film with clips.Examples of the diagonal stretching method may include a stretchingmethod in which the primary film is continuously stretched in thediagonal direction using a tenter stretching machine which is capable ofapplying a feeding force, tensile force, or take-up force at differentspeeds on left and right sides of the primary film in the longitudinalor width direction.

The stretching temperature in stretching of the primary film ispreferably “Tg−30”° C. or higher, and more preferably “Tg−10”° C. orhigher, and is preferably “Tg+60”° C. or lower, and more preferably“Tg+50”° C. or lower, relative to the glass transition temperature Tg ofthe alicyclic structure-containing polymer. When the stretching isperformed within such a temperature range, the polymer moleculecontained in the primary film can be appropriately oriented.

The stretching ratio in stretching of the primary film may beappropriately selected depending on desired optical properties,thickness, strength, and the like. The stretching ratio is usually 1.1times or more, more preferably 1.2 times or more, and more preferably1.5 times or more, and is usually 20 times or less, preferably 10 timesor less, and more preferably 5 times or less. Herein, for example, whenstretching is performed in a plurality of different directions as in thecase of the biaxial stretching method, the stretching ratio is the totalstretching ratio represented by the product of stretching ratios in therespective stretching directions. When the stretching ratio is equal toor less than the upper limit of the aforementioned range, a possibilityof rupture of the film can be reduced. Therefore, the resin film can beeasily produced.

When the primary film is subjected to the stretching treatment asdescribed above, the resin film having desired characteristics can beobtained. Further, generation of large crystal grains can be suppressedin the crystallization step by the stretching treatment of the primaryfilm. Therefore, whitening caused by the crystal grains can besuppressed, and the transparency of the resin film can be increased.

The thickness of the primary film may be optionally set in accordancewith the thickness of the resin film. The thickness of the primary filmis usually 5 μm or more, and preferably 10 μm or more, and is usually 1mm or less, and preferably 500 μm or less.

[2.2. Crystallization Step]

After the primary film is prepared, the crystallization step isperformed to crystallize the alicyclic structure-containing polymercontained in the primary film. In the crystallization step, thetemperature is set to be in the specific temperature range in a strainedstate where at least two sides of the primary film are held. In thismanner, the crystallization treatment of crystallizing the alicyclicstructure-containing polymer is performed.

The strained state of the primary film means a state where a tension isapplied to the primary film. However, this strained state of the primaryfilm does not include a state where the primary film is substantiallystretched. Herein, “substantially stretched” refers to a state where thestretching ratio of the primary film in any direction is usually 1.1times or more.

When the primary film is held, appropriate holding tools are used forholding. The holding tools may be a holding tool capable of continuouslyholding the primary film over the entire length of the sides, orintermittently holding the primary film with intervals. For example, thesides of the primary film may be intermittently held by holding toolsdisposed at specific intervals.

In the crystallization step, the primary film is kept in a strainedstate where at least two sides of the primary film are held. Thus,deformation due to thermal shrinkage of the primary film at a regionbetween the held sides is prevented. In order to prevent deformation ata wide area of the primary film, it is preferable that sides includingtwo opposite sides are held to keep the region between the held sides ina strained state. For example, in the case of the primary film which hasa rectangular sheet piece form, two opposite sides (for example, longsides or short sides) are held to keep the region between the two sidesin a strained state. Thus, deformation over the entire surface of theprimary film in the sheet piece form can be prevented. In thelong-length primary film, two sides at end portions in the widthdirection (i.e., long sides) are held to keep the region between the twosides in a strained state. Thus, deformation over the entire surface ofthe long-length primary film can be prevented. In such a primary filmwhose deformation is prevented as described above, even when a stress inthe film is caused by thermal shrinkage, occurrence of deformation suchas wrinkle is suppressed. When a stretched film which has been subjectedto the stretching treatment is used as the primary film, at least twosides which are orthogonal to the stretching direction (in a case ofbiaxial stretching, the stretching direction in which the stretchingratio is larger) may be held, whereby deformation is more certainlysuppressed.

In order to more surely suppress the deformation in the crystallizationstep, it is preferable that a larger number of sides are held. Forexample, regarding the primary film in the sheet piece form, it ispreferable that all sides thereof are held. Specifically, it ispreferable that four sides of the primary film in the rectangular sheetpiece form are held.

It is preferable that the holding tools which can hold the sides of theprimary film is a holding tool which does not come into contact with theprimary film at a part other than the sides of the primary film. Whensuch holding tools are used, a resin film having more excellentsmoothness can be obtained.

It is preferable that the holding tools are those which can fix arelative position between the holding tools in the crystallization step.As the position between the holding tools does not relatively shift inthe crystallization step, the holding tools is advantageous forsuppressing substantial stretching of the primary film in thecrystallization step.

Suitable examples of the holding tools may include grippers which areprovided in a frame at specific intervals as holding tools for therectangular primary film and can grip the sides of the primary film,such as clips. Examples of holding tools for holding two sides at endportions of the width direction of the long-length primary film mayinclude grippers which are provided to a tenter stretching machine andcan grip the sides of the primary film.

When the long-length primary film is used, sides at end portions of theprimary film in the longitudinal direction (i.e., short sides) may beheld. However, instead of holding these sides, both side areas in thelongitudinal direction of a region of the primary film which issubjected to the crystallization treatment may also be held. Forexample, at the both side areas in the longitudinal direction of theregion of the primary film which is subjected to the crystallizationtreatment, a holding device that can hold the primary film so that theprimary film is not thermally shrunk but is held in a strained state maybe provided. Examples of the holding device may include a combination oftwo rolls and a combination of an extruder and a take-up roll. Byapplying with these combination a tension such as a conveyance tensionto the primary film, thermal shrinkage of the primary film at the regionwhich is subjected to the crystallization treatment can be suppressed.Therefore, when the combination is used as the holding device, theprimary film can be held while the primary film is conveyed in thelongitudinal direction. Thereby the resin film can be efficientlyproduced.

In the crystallization step, the temperature of the primary film is setto a temperature which is equal to or higher than the glass transitiontemperature Tg of the alicyclic structure-containing polymer and equalto or lower than the melting point Tm of the alicyclicstructure-containing polymer in the strained state where at least twosides of the primary film are held as described above. In the primaryfilm which is set to the temperature described above, crystallization ofthe alicyclic structure-containing polymer proceeds. As a result, acrystallized film containing a crystallized alicyclicstructure-containing polymer is obtained by this crystallization step.At that time, the crystallized film is kept in the strained state whiledeformation of the film is prevented. Therefore, the crystallization canbe advanced without impairing the smoothness of the crystallized film.

The temperature range in the crystallization step may be optionally setto a temperature range which is equal to or higher than the glasstransition temperature Tg of the alicyclic structure-containing polymerand equal to or lower than the melting point Tm of the alicyclicstructure-containing polymer, as described above. In particular, it ispreferable that the temperature is set to a temperature at which thespeed of crystallization is increased. The temperature of the primaryfilm in the crystallization step is preferably “Tg+20”° C. or higher,and more preferably “Tg+30”° C. or higher, and is preferably “Tm−20”° C.or lower, and more preferably “Tm−40”° C. or lower. When the temperaturein the crystallization step is equal to or lower than the upper limit ofthe aforementioned range, clouding of the resin film can be suppressed.Therefore, a resin film suitable for use as an optical film is obtained.

When the temperature of the primary film is set to the temperaturedescribed above, the primary film is usually heated. It is preferablethat a heating device for this heating is a heating device which canincrease the atmospheric temperature around the primary film as aphysical contact of the heating device with the primary film isunnecessary. Specific examples of the suitable heating device mayinclude an oven and a heating furnace.

The treatment time of maintaining the temperature of the primary film tothe aforementioned temperature range in the crystallization step ispreferably 1 second or more, and is more preferably 5 seconds or more,and preferably 30 minutes or less, and more preferably 10 minutes orless. When the crystallization of the alicyclic structure-containingpolymer is sufficiently advanced in the crystallization step, the heatresistance of the resin film can be enhanced. When the treatment time isequal to or less than the upper limit of the aforementioned range,clouding of the resin film can be suppressed. Therefore, a resin filmsuitable for use as an optical film is obtained.

[2.3. Relaxation Step]

In order to effect residual stress removal by thermal shrinkage of thecrystallized film obtained in the crystallization step, the relaxationstep is performed after the crystallization step. In the relaxationstep, while the crystallized film obtained in the crystallization stepis kept flat, a relaxation treatment of relaxing the strain of thecrystallized film at a temperature in a specific temperature range isperformed.

Relaxing the strain of the crystallized film refers to release of thecrystallized film from the strained state held by the holding device.When the crystallized film is not strained, the crystallized film may beheld by the holding device. When the strain is relaxed as describedabove, the crystallized film becomes in a state where the crystallizedfilm is thermally shrinkable. In the relaxation step, a stress which maybe generated in the resin film during heating is canceled by effectingthermal shrinkage of the crystallized film. Therefore, thermal shrinkageof the resin film of the present invention in a high-temperatureenvironment can be reduced. Accordingly, a resin film having excellentsize stability in a high-temperature environment is obtained.

Relaxation of the strain of the crystallized film may be performed atonce, and may also be performed over a period of time in a continuous orstepwise manner. In order to suppress occurrence of deformation such aswaviness and wrinkle of the resin film to be obtained, it is preferablethat the relaxation of the strain is performed in a continuous orstepwise manner.

Relaxation of the strain of the crystallized film is performed while thecrystallized film is kept flat. “Keeping the crystallized film flat”refers to an operation of keeping the crystallized film in a flat shapeso that deformation such as waviness and wrinkle are not caused. Thus,occurrence of deformation such as waviness and wrinkle of the resin filmto be obtained can be suppressed.

The treatment temperature of the crystallized film during the relaxationtreatment may be set to a temperature range which is equal to or higherthan the glass transition temperature Tg of the alicyclicstructure-containing polymer and equal to or lower than the meltingpoint Tm of the alicyclic structure-containing polymer. Specifictreatment temperature may be set depending on the type of the alicyclicstructure-containing polymer. For example, when the hydrogenated productof the ring-opened polymer of dicyclopentadiene is used as the alicyclicstructure-containing polymer, the treatment temperature is preferably“Tg+20”° C. or higher, and more preferably “Tg+30”° C. or higher, and ispreferably “Tm−20”° C. or lower, and more preferably “Tm−40”° C. orlower. When the relaxation step is performed without cooling after thecrystallization step, it is preferable that the treatment temperature ofthe crystallized film in the relaxation step is the same as thetemperature in the crystallization step. Thereby unevenness of thetemperature of the crystallized film in the relaxation step can besuppressed, and the productivity of the resin film can be enhanced.

The treatment time of maintaining the temperature of the crystallizedfilm within the temperature range in the crystallization step ispreferably 1 second or more, and more preferably 5 seconds or more, andpreferably 10 minutes or less. When the treatment time is equal to ormore than the lower limit value of the aforementioned range, the sizestability of the resin film of the present invention in ahigh-temperature environment can be efficiently enhanced. When it isequal to or less than the upper limit value thereof, the size stabilityof the resin film of the present invention in a high-temperatureenvironment can be efficiently enhanced, and clouding of the resin filmdue to advance of crystallization in the relaxation step can besuppressed.

When the crystallized film in a sheet piece form is subjected to therelaxation treatment in the relaxation step as described above, forexample, a method of holding four sides of the crystallized film andnarrowing intervals between held portions in a continuous or stepwisemanner may be used. In this case, the intervals between the heldportions at each of four sides of the crystallized film may besimultaneously narrowed. The intervals between the held portions at apart of the sides may be narrowed, and the intervals between the heldportions at another part of the sides may be then narrowed. Further, theintervals between the held portions at a part of the sides may bemaintained without narrowing. Alternatively, the intervals between theheld portions at a part of the sides may be narrowed in a continuous orstepwise manner, while the intervals between the held portions atanother part of the sides may be narrowed at once.

When the long-length crystallized film is subjected to the relaxationtreatment in the relaxation step as described above, for example, amethod of narrowing intervals between guide rails which can guide clipsin the conveyance direction of the crystallized film or narrowingintervals between adjacent clips using a tenter stretching machine maybe used.

When the relaxation of the strain of the crystallized film is performedas described above by narrowing of the intervals between the heldportions while the crystallized film is held, a degree of narrowing theintervals may be set depending on the magnitude of a stress remaining inthe crystallized film obtained in the crystallization step.

For example, when a stretched film which has been subjected to astretching treatment is used as the primary film, a large stress tendsto remain in the crystallized film obtained in the crystallization step.For this reason, it is preferable that the degree of narrowing theintervals to relax the strain of the crystallized film is large. Forexample, when an unstretched film which is not subjected to a stretchingtreatment is used as the primary film, a small stress tends to remain inthe crystallized film obtained in the crystallization step. For thisreason, it is preferable that the degree of narrowing the intervals torelax the strain of the crystallized film is small.

The degree of narrowing the held intervals in the relaxation step isusually 0.1S or more, preferably 0.5S or more, and more preferably 0.7Sor more, and is usually 1.2S or less, preferably 1.0S or less, and morepreferably 0.95S or less, wherein S is a thermal shrinkage ratio (%) ina state where the crystallized film is not strained at the treatmenttemperature of the crystallized film in the relaxation step. When theaforementioned thermal shrinkage ratio S is anisotropic such as in acase wherein thermal shrinkage ratios S in two orthogonal directions aredifferent, the degree of narrowing the held intervals can be set withinthe aforementioned range in each direction. When the degree falls withinsuch a range, the residual stress of the resin film can be sufficientlyremoved and flatness can be maintained.

The thermal shrinkage ratio S of the crystallized film may be measuredby the following method.

The crystallized film is cut out to be a square shape with a size of 150mm×150 mm in an environment at a room temperature of 23° C., to obtain asample film. This sample film is heated in an oven the temperature ofwhich is set to the same as the treatment temperature in the relaxationstep for 60 minutes, and cooled to 23° C. (room temperature). Then, thelengths of two sides parallel to a direction in which the thermalshrinkage ratio S of the sample film is to be determined are measured.

The thermal shrinkage ratio S of the sample film is calculated by thefollowing equation (III) on the basis of the measured length of each oftwo sides. In the equation (III), L₁ is the length of one of themeasured two sides of the heated sample film, and L₂ is the length ofthe other side.Thermal shrinkage ratio S (%)=[(300−L ₁ −L ₂)/300]×100  (III)

[2.4. First Example of Crystallization Step and Relaxation Step]

Hereinafter, a first example of the crystallization step and therelaxation step described above will be described. The first example isan example of a method for producing a resin film in a sheet piece formusing a primary film in a sheet piece form. The crystallization step andthe relaxation step are not limited to the first example.

FIGS. 1 and 2 are plan views schematically illustrating an example of aholding device.

As shown in FIG. 1, a holding device 100 is a device for holding aprimary film 10 in a sheet piece form, and includes a frame 110, andclips 121, 122, 123, and 124 as a plurality of holding tools provided inthe frame 110 so as to allow adjustment of position. The clips 121, 122,123, and 124 are provided so as to be capable of gripping sides 11, 12,13, and 14 of the primary film 10, respectively.

When the crystallization step is performed using the holding device 100,the primary film 10 formed of a resin containing an alicyclicstructure-containing polymer is mounted on the holding device 100.Specifically, the primary film 10 is gripped by the clips 121 to 124.Thus, the four sides 11 to 14 of the primary film 10 are held, so thatthe primary film is strained. The primary film 10 in the strained stateis heated in an oven, which is not shown in the drawings, to atemperature in a range which is equal to or higher than the glasstransition temperature Tg of the alicyclic structure-containing polymercontained in the primary film 10 and equal to or lower than the meltingpoint Tm of the alicyclic structure-containing polymer.

As a result, the crystallization of the alicyclic structure-containingpolymer contained in the primary film 10 proceeds, to obtain acrystallized film 20 as shown in FIG. 2. At that time, the four sides 11to 14 of the primary film 10 are held so that the primary film 10 is ina strained state. Therefore, deformation due to thermal shrinkage doesnot occur in the crystallized film 20. Consequently, a stress that actstoward causing thermal shrinkage usually remains in the crystallizedfilm 20.

After that, the crystallized film 20 produced as described above issubjected to a relaxation step. When the crystallization step iscompleted, sides 21, 22, 23, and 24 of the crystallized film 20 are heldby the clips 121, 122, 123, and 124 of the holding device 100. In therelaxation step, while the crystallized film 20 is continuously heatedto a temperature in a range which is equal to or higher than the glasstransition temperature Tg of the alicyclic structure-containing polymerand equal to or lower than the melting point Tm of the alicyclicstructure-containing polymer, intervals I₁₂₁, I₁₂₂, I₁₂₃, and I₁₂₄between the clips 121 to 124 of the holding device 100 are narrowed.Thus, intervals between portions of the crystallized film 20 held by theclips 121 to 124 are narrowed in a manner of following the size changedue to thermal shrinkage of the crystallized film 20. Therefore, thestrain of the crystallized film 20 is relaxed while the crystallizedfilm 20 is kept flat, to obtain a resin film in a sheet piece form.

In the resin film thus obtained, a stress in the film which may causesize change in a high-temperature environment is canceled. Consequently,the size stability of the obtained resin film in a high-temperatureenvironment can be improved. Since the alicyclic structure-containingpolymer contained in the resin film is crystallized, the resin filmusually has excellent heat resistance.

[2.5. Second Example of Crystallization Step and Relaxation Step]

Hereinafter, a second example of the crystallization step and therelaxation step described above will be described. The second example isan example of a method for producing a long-length resin film using along-length primary film. The crystallization step and the relaxationstep are not limited to the second example.

FIG. 3 is a front view schematically illustrating an example of a deviceof producing a resin film. FIG. 4 is a plan view schematicallyillustrating the example of the device of producing the resin film.

As shown in FIGS. 3 and 4, a production device 200 includes a tenterstretching machine 300 as a holding device, conveying rolls 410 and 420,and an oven 500 as a heating device.

As shown in FIG. 4, the tenter stretching machine 300 includes endlesslink devices 310 and 320 which are provided at respective right and leftsides of a film conveyance path, and sprockets 330 and 340 for drivingthe link devices 310 and 320. The link devices 310 and 320 are providedwith a plurality of clips 311 and 321 as holding tools, respectively.

The clips 311 and 321 are provided so as to grip sides 31 and 32 at endportions in the width direction of a primary film 30, sides 41 and 42 atend portions in the width direction of a crystallized film 40, and sides51 and 52 at end portions of a resin film 50, for holding. The clips 311and 321 are provided so as to be movable with the rotation of the linkdevices 310 and 320.

The link devices 310 and 320 are provided so as to be rotatable bydriving by the sprockets 330 and 340 in a manner shown by arrows A310and A320 along circulating tracks defined by guide rails which are notshown in the drawings and are provided at each of the both sides of thefilm conveyance path. The clips 311 and 321 provided in the link devices310 and 320 are configured so as to be movable along desired circulatingtracks at the both sides of the film conveyance path.

By an appropriate optional mechanism, the clips 311 and 321 are providedso as to hold two sides 31 and 32 of the primary film 30 near an inlet510 of the oven 500, move along the film conveyance direction with therotation of the link devices 310 and 320 while the holding state ismaintained, and release the resin film 50 near an outlet 520 of the oven500.

This tenter stretching machine 300 is configured so as to be capable offreely adjusting intervals W_(MD) in the film conveyance directionbetween the clips 311 and 321 and intervals W_(TD) in the widthdirection between the clips 311 and 321. The example shown here is anexample in which the intervals W_(MD) and W_(TD) between the clips 311and 321 as described above are adjustable by the link devices 310 and320 which are pantograph-type link devices.

FIGS. 5 and 6 are plan views schematically illustrating a part of thelink device 310.

As shown in FIGS. 5 and 6, the link device 310 includes a plurality oflink plates 312 a to 312 d which are linked. In the link device 310shown in this example, the link plates 312 a to 312 d are annularlylinked. Thus, the shape of the link device 310 is endless.

The link device 310 also includes bearing rolls 313 a and 313 b. Thebearing rolls 313 a and 313 b are provided so as to pass in groovesformed by a guide rail not shown in the drawings. Therefore, thecirculating track of the link device 310 which is rotated along theguide rail may be adjusted by adjusting a track of the guide rail, and atraveling track of the clips 311 provided in the link device 310 may inturn be adjusted. Consequently, this link device 310 is configured sothat positions of the clips 311 in the width direction are changeable atany position in the film conveyance direction by adjusting the track ofthe guide rail. Thus, the intervals W_(TD) in the width directionbetween the clips 311 and 321 are changeable by changing the positionsof the clips 311 in the width direction.

As shown in FIGS. 5 and 6, one unit of the link device 310 includes: (a)the link plate 312 a which has a fulcrum on each of the outside bearingroll 313 a and the inside bearing roll 313 b, extends inwards, and hasthe clip 311 at an inside end thereof; (b) the link plate 312 b whichhas a common fulcrum on the link plate 312 a and the bearing roll 313 band extends to another fulcrum on another bearing roll 313 a; (c) thelink plate 312 c which has a fulcrum between the fulcrums of the linkplate 312 b, extends therefrom inwards, and has the clip 311 at aninside end thereof; and (d) the link plate 312 d which has a fulcrumbetween the inside end and an outside end of the link plate 312 c,extends therefrom outwards, and has a fulcrum on a link plate 312 a of aunit adjacent thereto. Herein, the outside means a side remote from thefilm conveyance path, and the inside means a side close to the filmconveyance path. In this link device 310, the state of link pitch can bechanged between contraction and expansion states in accordance withdistances D1 and D2 of grooves of guide rolls. Therefore, this linkdevice 310 is configured so that the interval W_(MD) between the clips311 in the film conveyance direction can be changed at any position inthe film conveyance direction by adjusting the distances D1 and D2 ofthe grooves of the guide rolls.

The other link device 320 has the same configuration as that of the linkdevice 310 except that the link device is provided at a side opposite tothe link device 310 with respect to the film conveyance path. Therefore,the link device 320 is also configured so that the interval W_(MD)between the clips 321 in the film conveyance direction and positions ofthe clips 321 in the width direction can be adjusted in the same manneras the link device 310.

As shown in FIGS. 3 and 4, the conveying rolls 410 and 420 are providedat both sides of the tenter stretching machine 300 in the filmconveyance direction. The conveying roll 410 provided at the upstreamside of the tenter stretching machine 300 is a roll provided so as toconvey the primary film 30, and the conveying roll 420 provided at thedownstream side of the tenter stretching machine 300 is a roll providedso as to convey the resin film 50. The conveying rolls 410 and 420 areprovided so that a specific conveyance tension can be applied to theprimary film 30 for conveyance. Therefore, at both sides in thelongitudinal direction of the tenter stretching machine 300(corresponding to a region of the primary film 30 which is subjected toa crystallization treatment), the conveying rolls 410 and 420 canfunction as a holding device that can hold the primary film 30 so thatthe primary film 30 is not thermally shrunk but is held in a strainedstate.

As shown in FIG. 4, the oven 500 has a partition 530, and a space of theoven 500 is divided into a crystallization chamber 540 at the upstreamside and a relaxation chamber 550 at the downstream side by thepartition 530.

When the resin film 50 is produced using the production device 200described above, the long-length primary film 30 formed of the resincontaining an alicyclic structure-containing polymer is supplied to thetenter stretching machine 300 through the conveying roll 410.

As shown in FIG. 4, the primary film 30 supplied to the tenterstretching machine 300 is gripped by the clips 311 and 321 near theinlet 510 of the oven 500, and as a result, two sides 31 and 32 are heldby the clips 311 and 321. The primary film 30 held by the clips 311 and321 is kept in a strained state by being held by the clips 311 and 321and being held by the conveying rolls 410 and 420. The primary film 30is conveyed through the inlet 510 to the crystallization chamber 540 ofthe oven 500 while being in the strained state.

In the crystallization chamber 540, the primary film 30 is heated to atemperature range which is equal to or higher than the glass transitiontemperature Tg of the alicyclic structure-containing polymer containedin the primary film 30 and equal to or lower than the melting point Tmof the alicyclic structure-containing polymer, whereby thecrystallization step is performed. As a result, the crystallization ofthe alicyclic structure-containing polymer contained in the primary film30 proceeds, to obtain the crystallized film 40. At this time, two sides31 to 32 of the primary film 30 are held, so that the primary film 30 isin a strained state. Further, the primary film 30 is in a strained stateby being held by the conveying rolls 410 and 420. Therefore, deformationdue to thermal shrinkage does not occur in the crystallized film 40.Consequently, a stress that acts toward causing thermal shrinkageusually remains in the crystallized film 40.

After that, the produced crystallized film 40 is transferred to therelaxation chamber 550 of the oven 500 while two sides 41 and 42 areheld by the clips 311 and 321. In the relaxation chamber 550, while thecrystallized film 40 is continuously heated to a temperature in a rangewhich is equal to or higher than the glass transition temperature Tg ofthe alicyclic structure-containing polymer and equal to or lower thanthe melting point Tm of the alicyclic structure-containing polymer, theintervals W_(MD) between the clips 311 and 321 in the film conveyancedirection and the intervals W_(TD) between the clips 311 and 321 in thewidth direction are narrowed. As a result, the intervals between heldportions of the crystallized film 40 by the clips 311 and 321 arenarrowed in a manner of following the size change due to thermalshrinkage of the crystallized film 40. Therefore, the strain of thecrystallized film 40 is relaxed while the crystallized film 40 is keptflat, so that the long-length resin film 50 is obtained.

The resin film 50 is transferred through the outlet 520 to be sent outof the oven 500. The resin film 50 is released from the clips 311 and321 near the outlet 520 of the oven 500, transferred through theconveying roll 420, and collected.

In the resin film 50 thus obtained, a stress in the film which may causesize change in a high-temperature environment is canceled. Consequently,the size stability of the obtained resin film 50 in a high-temperatureenvironment can be improved. Since the alicyclic structure-containingpolymer contained in the resin film 50 is crystallized, the resin film50 usually has excellent heat resistance.

[2.6. Optional Step]

In the method for producing a resin film of the present invention, anoptional step may be further performed in combination with thecrystallization step and the relaxation step described above.

For example, the obtained resin film may be subjected to a surfacetreatment.

[3. Knurled Film]

The resin film of the present invention has excellent size stability ina high-temperature environment. Taking advantage of such an excellentproperty, the resin film of the present invention may be subjected to aknurling treatment using a laser beam. Hereinafter, the resin film whichhas been subjected to the knurling treatment is also referred to as“knurled film”.

FIG. 7 is a front view schematically illustrating an example of a schemeof producing a knurled film 60 where the resin film 50 is subjected to aknurling treatment.

As shown in FIG. 7, when the knurled film 60 is produced, the resin film50 is intermittently irradiated with a laser beam 610 from a laser beamirradiation device 600 while the resin film 50 is continuously conveyedin the longitudinal direction as shown by an arrow A50. When a surface53 of the resin film 50 is irradiated with the laser beam 610, hotmelting or ablation locally occurs on the surface 53 at a region whichis irradiated with the laser beam 610. As a result, a protrusion 61 maybe formed at the region which is irradiated with the laser beam 610, sothat the knurled film 60 having the protrusion 61 is obtained. In thiscase, occurrence of waviness and wrinkle in the knurled film 60 can besuppressed since the resin film 50 has excellent size stability in ahigh-temperature environment.

The irradiation time in one irradiation with the laser beam 610 inperforming the knurling treatment is preferably 0.001 ms or more, morepreferably 0.005 ms or more, and further preferably 0.01 ms or more, andis preferably 0.5 ms or less, more preferably 0.3 ms or less, andfurther preferably 0.1 ms or less. When the irradiation time with thelaser beam 610 falls within this range, the protrusion 61 of suitablesize can be easily formed.

As the laser beam 610, an ArF excimer laser beam, a KrF excimer laserbeam, a XeCl excimer laser beam, a third or fourth harmonic of a YAGlaser, a third or fourth harmonic of a YLF or YVO₄ solid state laser, aTi:S laser beam, a semiconductor laser beam, a fiber laser beam, acarbon dioxide gas laser beam, or the like may be used. Of these, acarbon dioxide gas laser beam is preferable from the viewpoint ofproductivity improvement with high output.

The output of the laser beam 610 is preferably 1 W or more, morepreferably 5 W or more, and further preferably 15 W or more, and ispreferably 30 W or less, and more preferably 25 W or less. When theoutput of the laser beam 610 is equal to or more than the lower limitvalue of the aforementioned range, insufficiency of irradiation dose ofthe laser beam 610 is prevented. Thus, the protrusion 61 can be stablyformed. When the output of the laser beam 610 is equal to or less thanthe upper limit value of the aforementioned range, generation of athrough hole in the resin film 50 can be prevented, and unintendedincrease of the protrusion 61 can be suppressed.

The light-condensing diameter of the laser beam 610 (i.e., the diameterfor a region irradiated with the laser beam 610) may be set depending onthe diameter of the protrusion 61. The light-condensing diameter of thelaser beam 610 is usually set to be smaller than the diameter of theprotrusion 61. Specific light-condensing diameter is preferably 100 μmor more, and more preferably 200 μm or more, and is preferably 500 μm orless, and more preferably 300 μm or less.

According to the knurling treatment by irradiation with the laser beam610 as described above, rupture of the resin film 50 during formation ofthe protrusion 61 can be prevented even when the resin film 50 is thin.Even when the resin film 50 is bent, the resin film 50 at the projection61 is unlikely to be ruptured. This may be because formation of theprotrusion 61 with the laser beam does not incur application of anunnecessary pressing force to the resin film 50, and as a result, aresidual stress is unlikely to remain in the resin film 50.

According to the knurling treatment by irradiation with the laser beam610, the protrusion 61 can be formed without abrasion and contaminationof the resin film 50.

FIG. 8 is a plan view schematically illustrating an example of theknurled film 60.

As shown in FIG. 8, the protrusion 61 is usually formed at an endportion in the width direction of the knurled film 60. Therefore, theknurled film 60 has band-shaped regions 62 and 63 where the protrusion61 is formed at both ends in the width direction of the knurled film 60.The widths W₆₂ and W₆₃ of the regions 62 and 63 are preferably 1.0 mm ormore, more preferably 2.0 mm or more, and particularly preferably 3.0 mmor more, and are preferably 12 mm or less, more preferably 11 mm orless, and particularly preferably 10 mm or less. When the widths W₆₂ andW₆₃ of the region 62 and 63 where the protrusion 61 is formed are equalto or more than the lower limit value of the aforementioned range,winding deviation of the knurled film 60 can be stably prevented. Whenthey are equal to or less than the upper limit value thereof, a validregion without the protrusion 61 can be widely ensured, and theproduction cost can be decreased.

When the thickness of the knurled film is about 20 μm or more, theaverage height of the protrusion 61 is preferably 0.5 μm or more, morepreferably 1.0 μm or more, and particularly preferably 2.0 μm or more,and is preferably 5.0 μm or less, more preferably 4.5 μm or less, andparticularly preferably 4.0 μm or less. When the thickness of theknurled film is less than 20 μm, the average height of the protrusion 61is preferably 2.5% or more, more preferably 5% or more, and furtherpreferably 10% or more of the thickness of the knurled film, and ispreferably 25% or less, more preferably 22.5% or less, and furtherpreferably 20% or less thereof. When the average height of theprotrusion 61 is equal to or more than the lower limit value of theaforementioned range, appearance failures caused by winding deviation,involution, and uneven thickness of the resin film 50 can be effectivelysuppressed. When it is equal to or less than the upper limit valuethereof, a crack can be stably prevented.

The diameter of the protrusion 61 is preferably 150 μm or more, morepreferably 200 μm or more, and particularly preferably 250 μm or more,and is preferably 600 μm or less, more preferably 550 μm or less, andparticularly preferably 500 μm or less. When the diameter of theprotrusion 61 is equal to or more than the lower limit value of theaforementioned range, an effect of the formed protrusion 61 can bestably exerted. When it is equal to or less than the upper limit valuethereof, local stress concentration on the protrusion 61 can be avoided.

In the knurling treatment using the laser beam 610, a cavity is usuallyformed at the center of the protrusion 61. The depth of the cavity ispreferably 2% or more, more preferably 4% or more, and particularlypreferably 8% or more of the thickness of the knurled film, and ispreferably 50% or less, more preferably 40% or less, and particularlypreferably 30% or less thereof. When the depth of the cavity fallswithin the aforementioned range, the effect of the formed protrusion 61can be stably exerted. Therefore, the appearance of a roll obtained bywinding the knurled film 60 can be improved.

The interval between the protrusions 61 in the longitudinal direction ofthe knurled film 60 is preferably 3.0 mm or more, more preferably 3.5 mmor more, and particularly preferably 4.0 mm or more, and is preferably7.0 mm or less, more preferably 6.5 mm or less, and particularlypreferably 6.0 mm or less. When the interval between the protrusions 61in the longitudinal direction is equal to or more than the lower limitvalue of the aforementioned range, blocking of the knurled film 60 canbe stably suppressed. When it is equal to or less than the upper limitvalue thereof, generation of a crack by local stress concentration onthe protrusion 61 can be suppressed.

The interval between the protrusions 61 in the width direction of theknurled film 60 is preferably 0.5 mm or more, more preferably 1.0 mm ormore, and particularly preferably 1.5 mm or more, and is preferably 6.0mm or less, more preferably 5.5 mm or less, and particularly preferably5.0 mm or less. When the interval between the protrusions 61 in thewidth direction is equal to or more than the lower limit value of theaforementioned range, blocking of the knurled film 60 can be stablysuppressed. When it is equal to or less than the upper limit valuethereof, a generation of crack by local stress concentration on theprotrusion 61 can be suppressed.

[4. Barrier Film]

The resin film of the present invention has excellent size stability ina high-temperature environment, as described above. Thereby filmformation can be performed in a preferable manner when a step of forminga film including a high-temperature process, such as a step of formingan inorganic layer, is performed. Specifically, the behavior of theresin film conveyed at the high-temperature process can be stabilized,and thermal damage against the resin film in a high-temperatureenvironment can be suppressed. Thus, a flat, uniform layer can beformed.

Taking advantage of such excellent properties, the resin film of thepresent invention may be used as a substrate film of a barrier film.This barrier film is a film having a multi-layered structure includingthe resin film of the present invention, and a barrier layer directly orindirectly provided on the resin film. Since the resin film usually hasexcellent adhesion property to the barrier layer, the barrier layer canbe directly provided on a surface of the resin film, but if necessary,the barrier layer may be provided through a base layer such as aflattening layer.

As a material for the barrier layer, for example, an inorganic materialmay be used. Examples of the inorganic material may include a materialcontaining a metal oxide, a metal nitride, a metal oxynitride, and amixture thereof. Examples of metals constituting the metal oxide, themetal nitride, and the metal oxynitride may include silicon andaluminum. In particular, silicon is preferable. Specific examples ofcompositions of the metal oxide, the metal nitride, and the metaloxynitride may include compositions represented by SiO_(x) (1.5<x<1.9),SiN_(y) (1.2<y<1.5), and SiO_(x)N_(y) (1<x<2 and 0<y<1), respectively.When such a material is used, a barrier film having excellenttransparency and barrier properties is obtained.

The thickness of the barrier layer is preferably 3 nm or more, and morepreferably 10 nm or more, and is preferably 2,000 nm or less, and morepreferably 1,000 nm or less.

The upper limit of moisture vapor permeability ratio of the barrierlayer is preferably 0.1 g/m²·day or less, and more preferably 0.01g/m²·day or less.

The barrier film may be produced by a production method including a stepof forming the barrier layer on the resin film of the present invention.The method of forming the barrier layer is not particularly limited. Forexample, the barrier layer may be formed by a film formation method,such as a vapor deposition method, a sputtering method, an ion platingmethod, an ion beam assist vapor deposition method, an arc dischargeplasma vapor deposition method, a thermal CVD method, and a plasma CVDmethod. In the arc discharge plasma method, vaporized particles havingproper energy are produced. Thus, a high-density barrier layer can beformed. When a plurality of types of components are simultaneouslyvapor-deposited or sputtered, a barrier layer containing the pluralityof types of components can be formed.

A specific example of the method of producing the barrier film asdescribed above will be described with reference to an example of adevice of performing the method. FIG. 9 is a cross-sectional viewschematically illustrating an example of a film formation device capableof forming the barrier layer as an inorganic layer by a CVD method.

As shown in FIG. 9, a film formation device 700 is a plasma CVD deviceof film-winding type, and performs a series of operations ofcontinuously forming the barrier layer by a CVD method on the resin film50 which is unwound from a roll 701 of the long-length resin film 50, toobtain a barrier film 70, and winding the barrier film 70 as a roll 702.

The film formation device 700 has a guide roll 711, a can roll 712, anda guide roll 713. The unwound resin film 50 can therewith be guided in adirection shown by an arrow A1, and subjected to a production process.When the positions of the guide roll 711, the can roll 712, and theguide roll 713 and tensions applied to the resin film 50 by the rollsare appropriately adjusted, the resin film 50 is brought into contactwith the can roll 712 during guiding by the can roll 712.

The can roll 712 rotates in a direction shown by an arrow A2, and theresin film 50 on the can roll 712 is conveyed in a state of being in thevicinity of a reaction tube 721. In this operation, an electric power isapplied to an electrode 722 from a power source 723, the can roll 712 isgrounded by an appropriate grounding means (not shown), and a gas of amaterial for the barrier layer is introduced in a direction of an arrowA3 from a gas introducing port 724. Thus, the barrier layer can becontinuously formed on a surface of the resin film 50. Such a series ofoperations is performed in a space surrounded by a vacuum chamber 790. Apressure in the vacuum chamber 790 may be decreased by an operation of avacuum exhaust device 730, and adjusted to a pressure suitable for theCVD method.

When the size stability of the resin film 50 in a high-temperatureenvironment is poor during such a process at high output, the resin film50 is likely to be floated from the can roll 212, and the resin film 50is likely to be deformed. Therefore, it may become difficult tocontinuously form a good barrier layer. However, since the resin film 50of the present invention has excellent size stability in ahigh-temperature environment, the floating as described above isunlikely to occur. When the resin film 50 of the present invention isused, a flat, uniform barrier layer can thus be continuously formed.Therefore, the barrier film 70 can be efficiently produced. Since theresin film 50 of the present invention has excellent heat resistance,thermal damage against the resin film 50 can be reduced. Therefore, thebarrier film 70 having small moisture vapor permeability ratio can beeasily produced.

The aforementioned barrier film may have an optional layer incombination with the resin film and the barrier layer. Examples of suchan optional layer may include an antistatic layer, a hard coat layer,and a contamination prevention layer. For example, the optional layerlike these may be formed by a method of applying a material for theoptional layer onto the barrier layer, followed by curing, a method ofattaching the layer by thermocompression bonding, or the like.

[5. Electroconductive Film]

The resin film of the present invention has excellent size stability ina high-temperature environment, as described above. Thereby filmformation can be performed in a preferable manner when a step of forminga film including a high-temperature process, such as a step of formingan inorganic layer, is performed.

Taking advantage of such excellent properties, the resin film of thepresent invention may be used as a substrate film of anelectroconductive film. This electroconductive film is a film having amulti-layered structure including the resin film of the presentinvention, and an electroconductive layer directly or indirectlyprovided on the resin film. Since the resin film usually has excellentadhesion property to the electroconductive layer, the electroconductivelayer can be directly provided on a surface of the resin film, but ifnecessary, the electroconductive layer may be provided through a baselayer such as a flattening layer.

As a material for the electroconductive layer, for example, anelectroconductive inorganic material may be used. In particular, amaterial which can form a transparent electroconductive layer ispreferably used. Examples of the inorganic material may include ITO(indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), IWO(indium tungsten oxide), ITiO (indium titanium oxide), AZO (aluminumzinc oxide), GZO (gallium zinc oxide), XZO (special zinc-based oxide),and IGZO (indium gallium zinc oxide).

The thickness of the electroconductive layer is preferably 30 nm ormore, and more preferably 50 nm or more, and is preferably 250 nm orless, and more preferably 220 nm or less.

When the electroconductive layer is formed, a function of an electrodecan be imparted to an electroconductive film thus obtained. The surfaceresistivity of a surface of the electroconductive film on a side of theelectroconductive layer may be appropriately selected in accordance witha purpose of use, and is usually 1,000 Ω/sq or less, and preferably 100Ω/sq or less.

The electroconductive film may be produced by a production methodincluding a step of forming the electroconductive layer on the resinfilm of the present invention. The method of forming theelectroconductive layer is not particularly limited. For example, theelectroconductive layer may be formed by a film formation method such asa sputtering method and a vapor deposition method. As described above,the resin film of the present invention has excellent size stability andheat resistance in a high-temperature environment. Therefore, the filmcan be formed at high output, and a flat electroconductive layer havingexcellent electroconductivity can be quickly formed.

The electroconductive film described above may have an optional layer,such as an optical functional layer and a barrier layer in combinationwith the resin film and the electroconductive layer.

EXAMPLE

Hereinafter, the present invention will be specifically described withreference to Examples. However, the present invention is not limited tothe following Examples. The present invention may be optionally modifiedand practiced without departing from the scope of claims of the presentinvention and the scope of their equivalents.

In the following description, “%” and “part” that represent an amountare on the basis of weight unless otherwise specified. Further, theoperations described below were performed under the conditions of normaltemperature and normal pressure unless otherwise specified. In thefollowing description, “sccm” is a unit of flow rate of a gas, andrepresents the amount of a gas which flows per minute, the amount beingrepresented by volumes (cm³) of the gas at 25° C. and 1 atm.

[Evaluation Method]

[Method for Measuring Weight Average Molecular Weight and Number AverageMolecular Weight]

The weight average molecular weight and the number average molecularweight of the polymer were measured in terms of polystyrene by using agel permeation chromatography (GPC) system (“HLC-8320” manufactured byTosoh Corporation). In the measurement, an H-type column (manufacturedby Tosoh Corporation) was used as a column, and tetrahydrofuran was usedas a solvent. The measurement was performed at a temperature of 40° C.

[Method for Measuring Glass Transition Temperature Tg and Melting PointTm]

A sample that had been heated to 300° C. in a nitrogen atmosphere wasrapidly cooled with liquid nitrogen, and the glass transitiontemperature Tg and the melting point Tm of the sample were eachdetermined by increasing the temperature at 10° C./min using adifferential operation calorimeter (DSC).

[Method for Measuring Hydrogenation Ratio of Polymer]

The hydrogenation ratio of the polymer was measured by ¹H-NMRmeasurement at 145° C. using orthodichlorobenzene-d⁴ as a solvent.

[Method for Measuring Ratio of Racemo Diads of Polymer]

The polymer was subjected to ¹³C-NMR measurement at 200° C. by aninverse-gated decoupling method using orthodichlorobenzene-d⁴ as asolvent. From the result of the ¹³C-NMR measurement, the ratio of racemodiads of the polymer was obtained on the basis of an intensity ratio ofthe signal at 43.35 ppm derived from meso diads and the signal at 43.43ppm derived from racemo diads using the peak of orthodichlorobenzene-d⁴at 127.5 ppm as a reference shift.

[Method for Measuring Total Light Transmittance of Film]

The total light transmittance of the film was measured at a wavelengthrange of 400 nm to 700 nm with an ultraviolet-visible spectrophotometer(“V-550” manufactured by JASCO Corporation).

[Method for Measuring Haze of Film]

The film of a randomly selected portion was cut out to obtain a thinfilm sample having a square shape with a size of 50 mm×50 mm.Subsequently, the haze of the thin film sample was measured with a hazemeter (“NDH5000” manufactured by Nippon Denshoku Industries Co., Ltd.).

[Method for Measuring Thermal Size Change Ratio of Film]

The film was cut out to be a square shape with a size of 150 mm×150 mmin an environment at a room temperature of 23° C., to obtain a samplefilm. This sample film was heated in an oven of 150° C. for 60 minutes,and cooled to 23° C. (room temperature). The lengths of four sides andtwo diagonal lines of the sample film were measured.

The thermal size change ratio of the sample film was calculated by thefollowing equation (I) on the basis of the measured length of each offour sides. In the equation (I), L_(A) is the length of each side of theheated sample film.Thermal size change ratio (%)=[(L _(A)−150)/150]×100  (I)

The thermal size change ratio of the sample film was also calculated bythe following equation (II) on the basis of the measured length of eachof two diagonal lines. In the equation (II), L_(D) is the length of eachdiagonal line of the heated sample film.Thermal size change ratio (%)=[(L _(D)−212.13)/212.13]×100  (II)

The value whose absolute value was maximum among six calculated valuesof thermal size change ratio was employed as the thermal size changeratio of the film.

[Method for Measuring Thermal Shrinkage Ratio S of Crystallized Film]

The crystallized film was cut out to be a square shape with a size of150 mm×150 mm in an environment at a room temperature of 23° C., toobtain a sample film. This sample film was heated in an oven thetemperature of which was set to the same as the treatment temperature inthe relaxation step for 60 minutes, and cooled to 23° C. (roomtemperature). Then, the lengths of two sides parallel to a direction inwhich the thermal shrinkage ratio S of the sample film is to bedetermined were measured.

The thermal shrinkage ratio S of the sample film was calculated by thefollowing equation (III) on the basis of the measured length of each oftwo sides. In the equation (III), L₁ is the length of one of themeasured two sides of the heated sample film, and L₂ is the length ofthe other side.Thermal shrinkage ratio S (%)=[(300−L ₁ −L ₂)/300]×100  (III)

[Method for Evaluating Laser Processability of Film]

The film was cut out to be a square shape with a size of 30 mm×30 mm, toobtain a sample film. A region of 20 mm×20 mm at the center of thesample film was irradiated with a laser beam, to form a plurality ofprotrusions. In this operation, as an irradiation device of a laserbeam, a CO₂ laser beam irradiation device (“MLZ9510” manufactured byKeyence Corporation, laser wavelength: 10.6 μm) was used. Theirradiation intensity of a laser beam was 20 W. The irradiation time inone irradiation of a laser beam and the size of a region where the laserbeam impinged on the sample film were adjusted so as to obtain theprotrusions with a diameter of 200 μm in a dot shape.

Thus, the protrusions were formed on the sample film in the dot shapewhere a total of 36 protrusions of 6 lines and 6 columns were disposedat intervals of 4 mm in each of lengthwise and transverse directions.

Subsequently, the sample film was placed on a flat stage with a surfaceof the sample film which was irradiated with the laser beam facedupward. On the sample film, a glass plate with a thickness of 1.2 mm anda size of 50 mm in length and 50 mm in width was placed. The thicknessof the sample film at each of the formed protrusions in this state(i.e., the height from the stage to an apex of the protrusion) wasmeasured with an ultra-deep microscope (“VK-9500” manufactured byKeyence Corporation). A difference between the maximum and minimumvalues of the measured values was determined as a deformation amount ofthe film by the irradiation with the laser beam.

This deformation amount represents a degree of flatness which is lost bybending of the film when the film is locally shrunk by heat generated inthe film in which the laser beam is absorbed. Therefore, a smallerdeformation amount represents that the film has better laserprocessability.

Production Example 1 Production of Hydrogenated Product of Ring-OpenedPolymer of Dicyclopentadiene

A metal pressure-resistant reaction vessel was sufficiently dried andthe inside thereof was replaced with nitrogen. To the metalpressure-resistant reaction vessel, 154.5 parts of cyclohexane, 42.8parts of a cyclohexane solution of dicyclopentadiene (endo isomercontent: 99% or more) in a concentration of 70% (amount ofdicyclopentadiene: 30 parts), and 1.9 parts of 1-hexene were added, andheated to 53° C.

0.061 parts of an n-hexane solution of diethylaluminum ethoxide in aconcentration of 19% was added to a solution prepared by dissolving0.014 parts of tetrachloro tungsten phenylimide(tetrahydrofuran) complexin 0.70 parts of toluene, and the mixture was stirred for 10 minutes toprepare a catalyst solution.

The catalyst solution was added to the pressure-resistant reactionvessel to initiate a ring-opening polymerization reaction. After that,the reaction was performed for 4 hours while the temperature wasmaintained at 53° C., to obtain a solution of a ring-opened polymer ofdicyclopentadiene.

The number-average molecular weight (Mn) and the weight-averagemolecular weight (Mw) of the obtained ring-opened polymer ofdicyclopentadiene were 8,750 and 28,100, respectively, and the molecularweight distribution (Mw/Mn) calculated therefrom was 3.21.

To 200 parts of the obtained solution of the ring-opened polymer ofdicyclopentadiene, 0.037 parts of 1,2-ethanediol as a terminator wasadded. The mixture was heated to 60° C. and stirred for 1 hour, toterminate the polymerization reaction. To the mixture, 1 part of ahydrotalcite-like compound (“KYOWAAD (registered trademark) 2000”available from Kyowa Chemical Industry Co., Ltd.) was added. The mixturewas heated to 60° C. and stirred for 1 hour. After that, 0.4 parts of afiltration aid (“RADIOLITE (registered trademark) #1500” available fromShowa Chemical Industry Co., Ltd.) was added, and the mixture wasfiltered through a PP pleats cartridge filter (“TCP-HX” available fromAdvantec Toyo Kaisha, Ltd.) to separate the adsorbent and the solution.

To 200 parts of the filtered solution of the ring-opened polymer ofdicyclopentadiene (amount of the polymer: 30 parts), 100 parts ofcyclohexane was added. 0.0043 parts of chlorohydridecarbonyltris(triphenylphosphine) ruthenium was then added, and a hydrogenationreaction was performed at a hydrogen pressure of 6 MPa and 180° C. for 4hours. As a result, a reaction liquid containing a hydrogenated productof the ring-opened polymer of dicyclopentadiene was obtained. Thisreaction liquid was a slurry solution in which the hydrogenated productswere precipitated.

The hydrogenated products contained in the reaction liquid wereseparated from the solution using a centrifugal separator, and driedunder reduced pressure at 60° C. for 24 hours, to obtain 28.5 parts ofthe hydrogenated products of the ring-opened polymer ofdicyclopentadiene having crystallizability. The hydrogenation ratio ofthe hydrogenated products was 99% or more, the glass transitiontemperature Tg was 93° C., the melting point (Tm) was 262° C., and theratio of racemo diads was 89%.

Production Example 2 Production of Unstretched Film

To 100 parts of the hydrogenated products of the ring-opened polymer ofdicyclopentadiene obtained in Production Example 1, 1.1 parts of anantioxidant(tetrakis[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane;“Irganox (registered trademark) 1010” available from BASF Japan Ltd.)was added, to obtain a resin as a material for the film.

The aforementioned resin was put into a twin-screw extruder (“TEM-37B”manufactured by Toshiba Machine Co., Ltd.) provided with four die holeseach having an inner diameter of 3 mmϕ. The resin was molded by hot meltextrusion molding using the twin-screw extruder, to obtain a moldedarticle in a strand shape. The molded article was finely cut with astrand cutter, to obtain pellets of the resin. The operation conditionsof the twin-screw extruder are as follows.

Barrel setting temperature: 270° C. to 280° C.

Die setting temperature: 250° C.

Screw rotation speed: 145 rpm

Feeder rotation speed: 50 rpm

Subsequently, the obtained pellets were supplied to a hot melt extrusionfilm-molding machine provided with a T die. A long-length unstretchedfilm (thickness: 150 μm, width: 120 mm) formed of the aforementionedresin was produced using this film-molding machine by a method in whichthe film was wound into a roll at a speed of 2 m/min. The operationconditions of the film-molding machine are as follows.

Barrel setting temperature: 280° C. to 290° C.

Die temperature: 270° C.

Screw rotation speed: 30 rpm

The haze of the obtained unstretched film was measured and found to be0.3%.

Example 1

[1-1. Stretching Step]

A randomly selected portion of the long-length unstretched film obtainedin Production Example 2 was cut out to be a square shape with a size of90 mm×90 mm. The cutting was performed so that sides of the cut squareof the unstretched film were parallel to the longitudinal or widthdirection of the long-length unstretched film. The cut unstretched filmwas set in a compact stretching machine (“EX10-B type” manufactured byToyo Seiki Seisaku-sho, Ltd.). The compact stretching machine wasprovided with a plurality of clips for gripping four sides of the film,and was configured so that the film can be stretched by moving theclips. Using the compact stretching machine, the unstretched film wasstretched at a stretching ratio of two times in a lengthwise directioncorresponding to the longitudinal direction of the long-lengthunstretched film, and then stretched at a stretching ratio of two timesin a transverse direction corresponding to the width direction of thelong-length unstretched film, to obtain a stretched film as a primaryfilm. The operation conditions of the compact stretching machine are asfollows.

Stretching speed: 10,000 mm/min

Stretching temperature: 100° C.

[1-2. Crystallization Step]

A frame made of SUS capable of fixing four sides of the primary film wasprepared. Four sides of the aforementioned primary film were held by theframe, so that the primary film was kept at a strained state. Theprimary film was then subjected to a heating treatment in an oven at200° C. for 30 seconds, to perform a crystallization step ofcrystallizing the hydrogenated product of the ring-opened polymer ofdicyclopentadiene contained in the primary film. Thus, a crystallizedfilm was obtained.

The haze of the obtained crystallized film was measured and found to be0.4%. The thermal shrinkage ratio S of the crystallized film at 200° C.was measured by the aforementioned method, and found to be 3.2% in thelengthwise direction of the crystallized film and 4.1% in the transversedirection.

[1-3. Relaxation Step]

Four sides of the obtained crystallized film were gripped by the clipsof the compact stretching machine. Thus, the crystallized film was setin the compact stretching machine. A relaxation step of relaxing thestrain of the crystallized film was performed at 200° C. while thecrystallized film was kept flat, to obtain a resin film. At thisrelaxation step, the clips of the compact stretching machine were movedin an in-plane direction of the crystallized film, to decrease adistance between the clips, to thereby accomplish relaxation of thestrain of the crystallized film. The distance between the clips wasdecreased to 3.0% in the lengthwise direction of the crystallized film,and to 4.0% in the transverse direction of the crystallized film, over30 seconds.

The thermal size change ratio of the obtained resin film and thedeformation amount of the film by irradiation with a laser beam weremeasured by the aforementioned methods.

[1-4. Step of Producing Barrier Film]

A film formation device capable of forming a barrier layer on onesurface of the resin film by a CVD method was prepared. The filmformation device was a plasma CVD device of film-winding type which canform a desired barrier layer on a surface of a film conveyed in thedevice, like the film formation device shown in FIG. 9. However, thefilm formation device used herein has a structure by which the barrierlayer can be formed on the resin film fixed on a carrier film to formthe barrier layer on the resin films in a sheet piece form.Specifically, the prepared film formation device has a structure suchthat, when the resin film is fixed on a long-length carrier filmcontinuously conveyed in the device, a desired barrier layer can beformed on a surface of the resin film. As the carrier film, apolyethylene terephthalate film was used.

The obtained resin film was cut out to be a square shape with a size of100 mm×100 mm. The cut resin film was fixed on the carrier film with apolyimide tape. The carrier film was supplied to the film formationdevice, to form a barrier layer on one surface of the resin film. Thefilm formation conditions in this operation were a tetramethylsilane(TMS) flow rate of 10 sccm, an oxygen (O₂) flow rate of 100 sccm, anoutput of 0.8 kW, a total pressure of 5 Pa, and a film conveyance rateof 0.5 m/min. Film formation was performed by RF plasma discharge.

As a result, a barrier layer formed of SiO_(x) with a thickness of 300nm was formed on one surface of the resin film, to obtain a barrier filmhaving the barrier layer and the resin film.

For the obtained barrier film, appropriateness of film formation, curlamount, and adhesion were evaluated by the following methods.

(Method for Evaluating Appropriateness of Film Formation of BarrierLayer)

The surface state of the obtained barrier film was observed, andappropriateness of film formation was evaluated in accordance with thefollowing evaluation criteria.

Good: the film surface was flat or simply curled, and deformation suchas wrinkle and waviness did not occur.

Poor: on the film surface, deformation such as wrinkle and wavinessoccurred.

(Method for Evaluating Curl Amount of Barrier Film)

On a flat stage, the obtained barrier film was placed with the side ofthe barrier layer faced downward. The heights from the stage to the fourcorners of the barrier film which were floated from the stage weremeasured. The average of the measured heights was employed as the curlamount.

(Method for Evaluating Adhesion of Barrier Layer to Resin Film)

The obtained barrier film was subjected to a cross-cut test of 100pieces of 1-mm size squares in accordance with JIS K5400. A state of thebarrier layer peeled by a cellophane tape (specified by JIS Z1522) wasobserved. In this evaluation, the cellophane tape attached to the sideof the barrier layer was peeled, and the number of squares of thebarrier layer which were not peeled from the resin film was counted.Larger number of the squares of the barrier layer which were not peeledfrom the resin film is indicative of better adhesion of the barrierlayer to the resin film.

[1-5. Step of Producing Electroconductive Film]

A film formation device capable of forming an electroconductive layer onone surface of the resin film by a sputtering method was prepared. Thisfilm formation device was a magnetron sputtering device of film-windingtype capable of forming a desired electroconductive layer on a surfaceof the resin film which was fixed on a long-length carrier filmcontinuously conveyed in the device. As the carrier film, a polyethyleneterephthalate film was used.

The obtained resin film was cut out to be a square shape with a size of100 mm×100 mm. The cut resin film was fixed on the carrier film with apolyimide tape. The carrier film was supplied to the film formationdevice, to form an electroconductive layer on one surface of the resinfilm. In this operation, an In₂O₃—SnO₂ ceramic target was used as asputtering target. The film formation conditions were an argon (Ar) flowrate of 150 sccm, an oxygen (O₂) flow rate of 10 sccm, an output of 4.0kw, a degree of vacuum of 0.3 Pa, and a film conveyance rate of 0.5m/min.

As a result, a transparent electroconductive layer formed of ITO with athickness of 100 nm was formed on the surface of the resin film, toobtain an electroconductive film having the electroconductive layer andthe resin film.

For the obtained electroconductive film, appropriateness of filmformation, curl amount, and adhesion were evaluated by the followingmethods.

(Method for Evaluating Appropriateness of Film Formation ofElectroconductive Layer)

The surface state of the obtained electroconductive film was observed,and appropriateness of film formation was evaluated in accordance withthe following evaluation criteria.

Good: the film surface was flat or simply curled, and deformation suchas wrinkle and waviness did not occur.

Poor: on the film surface, deformation such as wrinkle and wavinessoccurred.

(Method for Evaluating Curl Amount of Electroconductive Film)

On a flat stage, the obtained electroconductive film was placed with theside of the electroconductive layer faced downward. The heights from thestage to the four corners of the electroconductive film which werefloated from the stage were measured. The average of the measuredheights was employed as the curl amount.

(Method for Evaluating Adhesion of Electroconductive Layer to ResinFilm)

The obtained electroconductive film was subjected to a cross-cut test of100 pieces of 1-mm size squares in accordance with JIS K5400. A state ofthe electroconductive layer peeled by a cellophane tape (specified byJIS Z1522) was observed. In this evaluation, the cellophane tapeattached to the side of the electroconductive layer was peeled, and thenumber of squares of the electroconductive layer which were not peeledfrom the resin film was counted. Larger number of squares of theelectroconductive layer which were not peeled from the resin film isindicative of better adhesion of the electroconductive layer to theresin film.

Example 2

Decreasing of the distance between clips was performed over 180 secondsin [1-3. Relaxation Step] described above. Except for the aforementionedchange, the same operation as in Example 1 was performed.

Example 3

The distance between clips in the lengthwise direction of thecrystallized film was not decreased in [1-3. Relaxation Step] describedabove. That is, the decrease ratio of distance between chucks in thelengthwise direction of the crystallized film was changed to 0.0% in therelaxation step. Except for the aforementioned change, the sameoperation as in Example 1 was performed.

Example 4

In [1-3. Relaxation Step] described above, the temperature at which thedistance between clips was decreased was changed to 170° C., decreasingof the distance between clips was performed over 60 seconds, and thedecrease ratio of distance between clips in the crystallized film waschanged to 2.5% in the lengthwise direction and to 3.5% in thetransverse direction. Except for the aforementioned changes, the sameoperation as in Example 1 was performed.

Example 5

In [1-2. Crystallization Step] described above, an unstretched filmbefore stretching was used as the primary film in place of the stretchedfilm produced in [1-1. Stretching Step]. Further, in [1-2.Crystallization Step] described above, the heating temperature waschanged to 220° C. Still further, in [1-3. Relaxation Step] describedabove, the decrease ratio of the distance between clips in each of thelengthwise and transverse directions of the crystallized film waschanged to 1.0%. Except for the aforementioned changes, the sameoperation as in Example 1 was performed.

Comparative Example 1

The [1-3. Relaxation Step] was not performed and the crystallized filmas it was was used as the resin film. Except for the aforementionedchanges, the same operation as in Example 1 was performed.

In Comparative Example 1, when the resin film was irradiated with alaser beam for evaluation of leaser processability, the resin film wasrolled and largely deformed as a result of local heating of the resinfilm by the laser beam.

In Comparative Example 1, the barrier film and the electroconductivefilm were largely curled and rounded. Therefore, it was impossible toperform the evaluation of curl amount.

Comparative Example 2

In [1-3. Relaxation Step] described above, the decrease ratio ofdistance between clips in the crystallized film was changed to 4.5% inthe lengthwise direction and to 6.0% in the transverse direction tothereby perform an excessive relaxation of the strain of thecrystallized film. Except for the aforementioned changes, the sameoperation as in Example 1 was performed.

In Comparative Example 2, the distance between clips in [1-3. RelaxationStep] was excessively decreased. As a result, the crystallized film wasnot kept flat during relaxation of strain, and deformation such aswaviness occurred in the obtained resin film. Consequently, it wasimpossible to produce a barrier film and an electroconductive film.

Comparative Example 3

In [1-3. Relaxation Step] described above, the decrease ratio ofdistance between clips in the crystallized film was changed to 1.5% inthe lengthwise direction and to 2.0% in the transverse direction tothereby insufficiently perform relaxation of the strain of thecrystallized film. Except for the aforementioned changes, the sameoperation as in Example 1 was performed.

Comparative Example 4

In [1-3. Relaxation Step] described above, the temperature at which thedistance between clips was decreased was changed to 110° C. anddecreasing of the distance between clips was performed over 180 seconds.Except for the aforementioned changes, the same operation as in Example1 was performed.

[Results]

Configurations of Examples and Comparative Examples are shown in Table1, and results thereof are shown in Table 2. Abbreviations in thefollowing Tables mean as follows.

“Decrease ratio”: the ratio of decreasing the distance between clips ina compact stretching machine in which the crystallized film was set inthe relaxation step. The distance between clips before movement of theclips was 100%.

“Transmittance”: a total light transmittance.

“Film deformation amount”: a deformation amount of the resin film byirradiation with a laser beam which is measured for evaluation of laserprocessability of the resin film.

TABLE 1 Configurations of Examples and Comparative ExamplesCrystallization Relaxation step step Decrease Temper- Temper- ratio (%)ature Time ature Time Trans- Length- Stretching (° C.) (sec.) (° C.)(sec.) verse wise Ex. 1 Sequential 200 30 200  30 4.0 3.0 Ex. 2 Biaxial200 30 200 180 4.0 3.0 Ex. 3 Stretching 200 30 200  30 4.0 0.0 Ex. 4 20030 170  60 3.5 2.5 Ex. 5 None 220 30 200  30 1.0 1.0 Comp. Sequential200 30 None Ex. 1 Comp. Biaxial 200 30 200  30 6.0 4.5 Ex. 2 Comp.Stretching 200 30 200  30 2.0 1.5 Ex. 3 Comp. 200 30 110 180 4.0 3.0 Ex.4

TABLE 2 Results of Examples and Comparative Examples Resin film Absolutevalue of thermal Film Barrier film Electroconductive film size deform-Appropri- Appropri- Transmit- change ation ateness Curl ateness CurlHaze tance ratio amount of film amount film amount (%) (%) (%) (μm)formation (mm) Adhesion formation (mm) Adhesion Ex. 1 0.4 89 0.05  4Good 18 100/100 Good 13 100/100 2 1.1 87 0.4  6 Good 22 100/100 Good 19100/100 3 0.4 89 0.9  7 Good 32 100/100 Good 27 100/100 4 0.4 89 0.7  6Good 25 100/100 Good 22 100/100 5 0.6 88 0.02  3 Good 21 100/100 Good 15100/100 Comp. Ex. 1 0.4 89 3.9 23 Poor *1  32/100 Poor *1  61/100 2 0.489 *2    *2 *3 *3 3 0.4 89 1.3 14 Poor *1  64/100 Poor 30  70/100 4 0.489 3.2 19 Poor *1  47/100 Poor *1  62/100 *1: The film was largelycurled and rounded, and it was thus impossible to perform the evaluationof curl amount. *2: Waviness deformation occurred in the film inlengthwise and transverse direction, and it was thus impossible toperform measurement. *3: The resin film could not be fixed on thecarrier film in a flat state, and film formation was thus not performed.

[Discussion]

The absolute values of the thermal size change ratios measured inExamples 1 to 5 are each the maximum value among absolute values ofthermal size change ratios measured in many directions. When it is foundthat the absolute value of the thermal size change ratio is sufficientlysmall, it can be confirmed that the absolute value of the thermal sizechange ratio of the resin film is small in any direction. In the resinfilms of Examples 1 to 5, the absolute values of the thermal size changeratios are small. This shows that the resin films of Examples 1 to 5have excellent size stability in a high-temperature environment.

It is confirmed that when the resin film of each of Examples 1 to 5 isused as a substrate film for forming a barrier layer, a good barrierfilm is obtained, and when the resin film is used as a substrate filmfor forming an electroconductive layer, a good electroconductive film isobtained.

REFERENCE SIGNS LIST

-   -   10: primary film    -   11, 12, 13 and 14: side of primary film    -   20: crystallized film    -   21, 22, 23 and 24: side of crystallized film    -   30: primary film    -   31 and 32: side of primary film    -   40: crystallized film    -   41 and 42: side of crystallized film    -   50: resin film    -   51 and 52: side of resin film    -   53: surface of resin film    -   60: knurled film    -   61: protrusion    -   62 and 63: region where protrusion is formed    -   70: barrier film    -   100: holding device    -   110: frame    -   121, 122, 123 and 124: clip    -   200: resin film production device    -   300: tenter stretching machine    -   310 and 320: link device    -   311 and 321: clip    -   312 a-312 d: link plate    -   313 a and 313 b: bearing roll    -   330 and 340: sprocket    -   410 and 420: conveying roll    -   500: oven    -   510: inlet of oven    -   520: outlet of oven    -   530: partition of oven    -   540: crystallization chamber    -   550: relaxation chamber    -   600: laser beam irradiation device    -   610: laser beam    -   700: film formation device    -   701: roll of resin film    -   702: roll of barrier film    -   711: guide roll    -   712: can roll    -   713: guide roll    -   721: reaction tube    -   722: electrode    -   723: electric power source    -   724: gas introducing port    -   730: vacuum exhaust device    -   790: vacuum chamber

The invention claimed is:
 1. A barrier film comprising: a resin film;and a barrier layer provided on the resin film; wherein the resin filmis formed of a resin containing an alicyclic structure-containingpolymer having crystallizability, an absolute value of a thermal sizechange ratio when the resin film is heated at 150° C. for 1 hour is 1%or less in any in-plane direction of the resin film, and the alicyclicstructure-containing polymer is a hydrogenated product of a ring-openedpolymer of dicyclopentadiene.
 2. An electroconductive film comprising: aresin film; and an electroconductive layer provided on the resin film;wherein the resin film is formed of a resin containing an alicyclicstructure-containing polymer having crystallizability, an absolute valueof a thermal size change ratio when the resin film is heated at 150° C.for 1 hour is 1% or less in any in-plane direction of the resin film,and the alicyclic structure-containing polymer is a hydrogenated productof a ring-opened polymer of dicyclopentadiene.